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/*! * chai * http://chaijs.com * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com> * MIT Licensed */ module.exports = function (chai, _) { var Assertion = chai.Assertion , AssertionError = chai.AssertionError , flag = _.flag; /** * ### Language Chains * * The following are provided as chainable getters to improve the readability * of your assertions. * * **Chains** * * - to * - be * - been * - is * - that * - which * - and * - has * - have * - with * - at * - of * - same * - but * - does * - still * * @name language chains * @namespace BDD * @api public */ [ 'to', 'be', 'been', 'is' , 'and', 'has', 'have', 'with' , 'that', 'which', 'at', 'of' , 'same', 'but', 'does', 'still' ].forEach(function (chain) { Assertion.addProperty(chain); }); /** * ### .not * * Negates all assertions that follow in the chain. * * expect(function () {}).to.not.throw(); * expect({a: 1}).to.not.have.property('b'); * expect([1, 2]).to.be.an('array').that.does.not.include(3); * * Just because you can negate any assertion with `.not` doesn't mean you * should. With great power comes great responsibility. It's often best to * assert that the one expected output was produced, rather than asserting * that one of countless unexpected outputs wasn't produced. See individual * assertions for specific guidance. * * expect(2).to.equal(2); // Recommended * expect(2).to.not.equal(1); // Not recommended * * @name not * @namespace BDD * @api public */ Assertion.addProperty('not', function () { flag(this, 'negate', true); }); /** * ### .deep * * Causes all `.equal`, `.include`, `.members`, `.keys`, and `.property` * assertions that follow in the chain to use deep equality instead of strict * (`===`) equality. See the `deep-eql` project page for info on the deep * equality algorithm: https://github.com/chaijs/deep-eql. * * // Target object deeply (but not strictly) equals `{a: 1}` * expect({a: 1}).to.deep.equal({a: 1}); * expect({a: 1}).to.not.equal({a: 1}); * * // Target array deeply (but not strictly) includes `{a: 1}` * expect([{a: 1}]).to.deep.include({a: 1}); * expect([{a: 1}]).to.not.include({a: 1}); * * // Target object deeply (but not strictly) includes `x: {a: 1}` * expect({x: {a: 1}}).to.deep.include({x: {a: 1}}); * expect({x: {a: 1}}).to.not.include({x: {a: 1}}); * * // Target array deeply (but not strictly) has member `{a: 1}` * expect([{a: 1}]).to.have.deep.members([{a: 1}]); * expect([{a: 1}]).to.not.have.members([{a: 1}]); * * // Target set deeply (but not strictly) has key `{a: 1}` * expect(new Set([{a: 1}])).to.have.deep.keys([{a: 1}]); * expect(new Set([{a: 1}])).to.not.have.keys([{a: 1}]); * * // Target object deeply (but not strictly) has property `x: {a: 1}` * expect({x: {a: 1}}).to.have.deep.property('x', {a: 1}); * expect({x: {a: 1}}).to.not.have.property('x', {a: 1}); * * @name deep * @namespace BDD * @api public */ Assertion.addProperty('deep', function () { flag(this, 'deep', true); }); /** * ### .nested * * Enables dot- and bracket-notation in all `.property` and `.include` * assertions that follow in the chain. * * expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]'); * expect({a: {b: ['x', 'y']}}).to.nested.include({'a.b[1]': 'y'}); * * If `.` or `[]` are part of an actual property name, they can be escaped by * adding two backslashes before them. * * expect({'.a': {'[b]': 'x'}}).to.have.nested.property('\\.a.\\[b\\]'); * expect({'.a': {'[b]': 'x'}}).to.nested.include({'\\.a.\\[b\\]': 'x'}); * * `.nested` cannot be combined with `.own`. * * @name nested * @namespace BDD * @api public */ Assertion.addProperty('nested', function () { flag(this, 'nested', true); }); /** * ### .own * * Causes all `.property` and `.include` assertions that follow in the chain * to ignore inherited properties. * * Object.prototype.b = 2; * * expect({a: 1}).to.have.own.property('a'); * expect({a: 1}).to.have.property('b'); * expect({a: 1}).to.not.have.own.property('b'); * * expect({a: 1}).to.own.include({a: 1}); * expect({a: 1}).to.include({b: 2}).but.not.own.include({b: 2}); * * `.own` cannot be combined with `.nested`. * * @name own * @namespace BDD * @api public */ Assertion.addProperty('own', function () { flag(this, 'own', true); }); /** * ### .ordered * * Causes all `.members` assertions that follow in the chain to require that * members be in the same order. * * expect([1, 2]).to.have.ordered.members([1, 2]) * .but.not.have.ordered.members([2, 1]); * * When `.include` and `.ordered` are combined, the ordering begins at the * start of both arrays. * * expect([1, 2, 3]).to.include.ordered.members([1, 2]) * .but.not.include.ordered.members([2, 3]); * * @name ordered * @namespace BDD * @api public */ Assertion.addProperty('ordered', function () { flag(this, 'ordered', true); }); /** * ### .any * * Causes all `.keys` assertions that follow in the chain to only require that * the target have at least one of the given keys. This is the opposite of * `.all`, which requires that the target have all of the given keys. * * expect({a: 1, b: 2}).to.not.have.any.keys('c', 'd'); * * See the `.keys` doc for guidance on when to use `.any` or `.all`. * * @name any * @namespace BDD * @api public */ Assertion.addProperty('any', function () { flag(this, 'any', true); flag(this, 'all', false); }); /** * ### .all * * Causes all `.keys` assertions that follow in the chain to require that the * target have all of the given keys. This is the opposite of `.any`, which * only requires that the target have at least one of the given keys. * * expect({a: 1, b: 2}).to.have.all.keys('a', 'b'); * * Note that `.all` is used by default when neither `.all` nor `.any` are * added earlier in the chain. However, it's often best to add `.all` anyway * because it improves readability. * * See the `.keys` doc for guidance on when to use `.any` or `.all`. * * @name all * @namespace BDD * @api public */ Assertion.addProperty('all', function () { flag(this, 'all', true); flag(this, 'any', false); }); /** * ### .a(type[, msg]) * * Asserts that the target's type is equal to the given string `type`. Types * are case insensitive. See the `type-detect` project page for info on the * type detection algorithm: https://github.com/chaijs/type-detect. * * expect('foo').to.be.a('string'); * expect({a: 1}).to.be.an('object'); * expect(null).to.be.a('null'); * expect(undefined).to.be.an('undefined'); * expect(new Error).to.be.an('error'); * expect(Promise.resolve()).to.be.a('promise'); * expect(new Float32Array).to.be.a('float32array'); * expect(Symbol()).to.be.a('symbol'); * * `.a` supports objects that have a custom type set via `Symbol.toStringTag`. * * var myObj = { * [Symbol.toStringTag]: 'myCustomType' * }; * * expect(myObj).to.be.a('myCustomType').but.not.an('object'); * * It's often best to use `.a` to check a target's type before making more * assertions on the same target. That way, you avoid unexpected behavior from * any assertion that does different things based on the target's type. * * expect([1, 2, 3]).to.be.an('array').that.includes(2); * expect([]).to.be.an('array').that.is.empty; * * Add `.not` earlier in the chain to negate `.a`. However, it's often best to * assert that the target is the expected type, rather than asserting that it * isn't one of many unexpected types. * * expect('foo').to.be.a('string'); // Recommended * expect('foo').to.not.be.an('array'); // Not recommended * * `.a` accepts an optional `msg` argument which is a custom error message to * show when the assertion fails. The message can also be given as the second * argument to `expect`. * * expect(1).to.be.a('string', 'nooo why fail??'); * expect(1, 'nooo why fail??').to.be.a('string'); * * `.a` can also be used as a language chain to improve the readability of * your assertions. * * expect({b: 2}).to.have.a.property('b'); * * The alias `.an` can be used interchangeably with `.a`. * * @name a * @alias an * @param {String} type * @param {String} msg _optional_ * @namespace BDD * @api public */ function an (type, msg) { if (msg) flag(this, 'message', msg); type = type.toLowerCase(); var obj = flag(this, 'object') , article = ~[ 'a', 'e', 'i', 'o', 'u' ].indexOf(type.charAt(0)) ? 'an ' : 'a '; this.assert( type === _.type(obj).toLowerCase() , 'expected #{this} to be ' + article + type , 'expected #{this} not to be ' + article + type ); } Assertion.addChainableMethod('an', an); Assertion.addChainableMethod('a', an); /** * ### .include(val[, msg]) * * When the target is a string, `.include` asserts that the given string `val` * is a substring of the target. * * expect('foobar').to.include('foo'); * * When the target is an array, `.include` asserts that the given `val` is a * member of the target. * * expect([1, 2, 3]).to.include(2); * * When the target is an object, `.include` asserts that the given object * `val`'s properties are a subset of the target's properties. * * expect({a: 1, b: 2, c: 3}).to.include({a: 1, b: 2}); * * When the target is a Set or WeakSet, `.include` asserts that the given `val` is a * member of the target. SameValueZero equality algorithm is used. * * expect(new Set([1, 2])).to.include(2); * * When the target is a Map, `.include` asserts that the given `val` is one of * the values of the target. SameValueZero equality algorithm is used. * * expect(new Map([['a', 1], ['b', 2]])).to.include(2); * * Because `.include` does different things based on the target's type, it's * important to check the target's type before using `.include`. See the `.a` * doc for info on testing a target's type. * * expect([1, 2, 3]).to.be.an('array').that.includes(2); * * By default, strict (`===`) equality is used to compare array members and * object properties. Add `.deep` earlier in the chain to use deep equality * instead (WeakSet targets are not supported). See the `deep-eql` project * page for info on the deep equality algorithm: https://github.com/chaijs/deep-eql. * * // Target array deeply (but not strictly) includes `{a: 1}` * expect([{a: 1}]).to.deep.include({a: 1}); * expect([{a: 1}]).to.not.include({a: 1}); * * // Target object deeply (but not strictly) includes `x: {a: 1}` * expect({x: {a: 1}}).to.deep.include({x: {a: 1}}); * expect({x: {a: 1}}).to.not.include({x: {a: 1}}); * * By default, all of the target's properties are searched when working with * objects. This includes properties that are inherited and/or non-enumerable. * Add `.own` earlier in the chain to exclude the target's inherited * properties from the search. * * Object.prototype.b = 2; * * expect({a: 1}).to.own.include({a: 1}); * expect({a: 1}).to.include({b: 2}).but.not.own.include({b: 2}); * * Note that a target object is always only searched for `val`'s own * enumerable properties. * * `.deep` and `.own` can be combined. * * expect({a: {b: 2}}).to.deep.own.include({a: {b: 2}}); * * Add `.nested` earlier in the chain to enable dot- and bracket-notation when * referencing nested properties. * * expect({a: {b: ['x', 'y']}}).to.nested.include({'a.b[1]': 'y'}); * * If `.` or `[]` are part of an actual property name, they can be escaped by * adding two backslashes before them. * * expect({'.a': {'[b]': 2}}).to.nested.include({'\\.a.\\[b\\]': 2}); * * `.deep` and `.nested` can be combined. * * expect({a: {b: [{c: 3}]}}).to.deep.nested.include({'a.b[0]': {c: 3}}); * * `.own` and `.nested` cannot be combined. * * Add `.not` earlier in the chain to negate `.include`. * * expect('foobar').to.not.include('taco'); * expect([1, 2, 3]).to.not.include(4); * * However, it's dangerous to negate `.include` when the target is an object. * The problem is that it creates uncertain expectations by asserting that the * target object doesn't have all of `val`'s key/value pairs but may or may * not have some of them. It's often best to identify the exact output that's * expected, and then write an assertion that only accepts that exact output. * * When the target object isn't even expected to have `val`'s keys, it's * often best to assert exactly that. * * expect({c: 3}).to.not.have.any.keys('a', 'b'); // Recommended * expect({c: 3}).to.not.include({a: 1, b: 2}); // Not recommended * * When the target object is expected to have `val`'s keys, it's often best to * assert that each of the properties has its expected value, rather than * asserting that each property doesn't have one of many unexpected values. * * expect({a: 3, b: 4}).to.include({a: 3, b: 4}); // Recommended * expect({a: 3, b: 4}).to.not.include({a: 1, b: 2}); // Not recommended * * `.include` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect([1, 2, 3]).to.include(4, 'nooo why fail??'); * expect([1, 2, 3], 'nooo why fail??').to.include(4); * * `.include` can also be used as a language chain, causing all `.members` and * `.keys` assertions that follow in the chain to require the target to be a * superset of the expected set, rather than an identical set. Note that * `.members` ignores duplicates in the subset when `.include` is added. * * // Target object's keys are a superset of ['a', 'b'] but not identical * expect({a: 1, b: 2, c: 3}).to.include.all.keys('a', 'b'); * expect({a: 1, b: 2, c: 3}).to.not.have.all.keys('a', 'b'); * * // Target array is a superset of [1, 2] but not identical * expect([1, 2, 3]).to.include.members([1, 2]); * expect([1, 2, 3]).to.not.have.members([1, 2]); * * // Duplicates in the subset are ignored * expect([1, 2, 3]).to.include.members([1, 2, 2, 2]); * * Note that adding `.any` earlier in the chain causes the `.keys` assertion * to ignore `.include`. * * // Both assertions are identical * expect({a: 1}).to.include.any.keys('a', 'b'); * expect({a: 1}).to.have.any.keys('a', 'b'); * * The aliases `.includes`, `.contain`, and `.contains` can be used * interchangeably with `.include`. * * @name include * @alias contain * @alias includes * @alias contains * @param {Mixed} val * @param {String} msg _optional_ * @namespace BDD * @api public */ function SameValueZero(a, b) { return (_.isNaN(a) && _.isNaN(b)) || a === b; } function includeChainingBehavior () { flag(this, 'contains', true); } function include (val, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , objType = _.type(obj).toLowerCase() , flagMsg = flag(this, 'message') , negate = flag(this, 'negate') , ssfi = flag(this, 'ssfi') , isDeep = flag(this, 'deep') , descriptor = isDeep ? 'deep ' : ''; flagMsg = flagMsg ? flagMsg + ': ' : ''; var included = false; switch (objType) { case 'string': included = obj.indexOf(val) !== -1; break; case 'weakset': if (isDeep) { throw new AssertionError( flagMsg + 'unable to use .deep.include with WeakSet', undefined, ssfi ); } included = obj.has(val); break; case 'map': var isEql = isDeep ? _.eql : SameValueZero; obj.forEach(function (item) { included = included || isEql(item, val); }); break; case 'set': if (isDeep) { obj.forEach(function (item) { included = included || _.eql(item, val); }); } else { included = obj.has(val); } break; case 'array': if (isDeep) { included = obj.some(function (item) { return _.eql(item, val); }) } else { included = obj.indexOf(val) !== -1; } break; default: // This block is for asserting a subset of properties in an object. // `_.expectTypes` isn't used here because `.include` should work with // objects with a custom `@@toStringTag`. if (val !== Object(val)) { throw new AssertionError( flagMsg + 'object tested must be an array, a map, an object,' + ' a set, a string, or a weakset, but ' + objType + ' given', undefined, ssfi ); } var props = Object.keys(val) , firstErr = null , numErrs = 0; props.forEach(function (prop) { var propAssertion = new Assertion(obj); _.transferFlags(this, propAssertion, true); flag(propAssertion, 'lockSsfi', true); if (!negate || props.length === 1) { propAssertion.property(prop, val[prop]); return; } try { propAssertion.property(prop, val[prop]); } catch (err) { if (!_.checkError.compatibleConstructor(err, AssertionError)) { throw err; } if (firstErr === null) firstErr = err; numErrs++; } }, this); // When validating .not.include with multiple properties, we only want // to throw an assertion error if all of the properties are included, // in which case we throw the first property assertion error that we // encountered. if (negate && props.length > 1 && numErrs === props.length) { throw firstErr; } return; } // Assert inclusion in collection or substring in a string. this.assert( included , 'expected #{this} to ' + descriptor + 'include ' + _.inspect(val) , 'expected #{this} to not ' + descriptor + 'include ' + _.inspect(val)); } Assertion.addChainableMethod('include', include, includeChainingBehavior); Assertion.addChainableMethod('contain', include, includeChainingBehavior); Assertion.addChainableMethod('contains', include, includeChainingBehavior); Assertion.addChainableMethod('includes', include, includeChainingBehavior); /** * ### .ok * * Asserts that the target is a truthy value (considered `true` in boolean context). * However, it's often best to assert that the target is strictly (`===`) or * deeply equal to its expected value. * * expect(1).to.equal(1); // Recommended * expect(1).to.be.ok; // Not recommended * * expect(true).to.be.true; // Recommended * expect(true).to.be.ok; // Not recommended * * Add `.not` earlier in the chain to negate `.ok`. * * expect(0).to.equal(0); // Recommended * expect(0).to.not.be.ok; // Not recommended * * expect(false).to.be.false; // Recommended * expect(false).to.not.be.ok; // Not recommended * * expect(null).to.be.null; // Recommended * expect(null).to.not.be.ok; // Not recommended * * expect(undefined).to.be.undefined; // Recommended * expect(undefined).to.not.be.ok; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(false, 'nooo why fail??').to.be.ok; * * @name ok * @namespace BDD * @api public */ Assertion.addProperty('ok', function () { this.assert( flag(this, 'object') , 'expected #{this} to be truthy' , 'expected #{this} to be falsy'); }); /** * ### .true * * Asserts that the target is strictly (`===`) equal to `true`. * * expect(true).to.be.true; * * Add `.not` earlier in the chain to negate `.true`. However, it's often best * to assert that the target is equal to its expected value, rather than not * equal to `true`. * * expect(false).to.be.false; // Recommended * expect(false).to.not.be.true; // Not recommended * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.true; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(false, 'nooo why fail??').to.be.true; * * @name true * @namespace BDD * @api public */ Assertion.addProperty('true', function () { this.assert( true === flag(this, 'object') , 'expected #{this} to be true' , 'expected #{this} to be false' , flag(this, 'negate') ? false : true ); }); /** * ### .false * * Asserts that the target is strictly (`===`) equal to `false`. * * expect(false).to.be.false; * * Add `.not` earlier in the chain to negate `.false`. However, it's often * best to assert that the target is equal to its expected value, rather than * not equal to `false`. * * expect(true).to.be.true; // Recommended * expect(true).to.not.be.false; // Not recommended * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.false; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(true, 'nooo why fail??').to.be.false; * * @name false * @namespace BDD * @api public */ Assertion.addProperty('false', function () { this.assert( false === flag(this, 'object') , 'expected #{this} to be false' , 'expected #{this} to be true' , flag(this, 'negate') ? true : false ); }); /** * ### .null * * Asserts that the target is strictly (`===`) equal to `null`. * * expect(null).to.be.null; * * Add `.not` earlier in the chain to negate `.null`. However, it's often best * to assert that the target is equal to its expected value, rather than not * equal to `null`. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.null; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(42, 'nooo why fail??').to.be.null; * * @name null * @namespace BDD * @api public */ Assertion.addProperty('null', function () { this.assert( null === flag(this, 'object') , 'expected #{this} to be null' , 'expected #{this} not to be null' ); }); /** * ### .undefined * * Asserts that the target is strictly (`===`) equal to `undefined`. * * expect(undefined).to.be.undefined; * * Add `.not` earlier in the chain to negate `.undefined`. However, it's often * best to assert that the target is equal to its expected value, rather than * not equal to `undefined`. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.undefined; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(42, 'nooo why fail??').to.be.undefined; * * @name undefined * @namespace BDD * @api public */ Assertion.addProperty('undefined', function () { this.assert( undefined === flag(this, 'object') , 'expected #{this} to be undefined' , 'expected #{this} not to be undefined' ); }); /** * ### .NaN * * Asserts that the target is exactly `NaN`. * * expect(NaN).to.be.NaN; * * Add `.not` earlier in the chain to negate `.NaN`. However, it's often best * to assert that the target is equal to its expected value, rather than not * equal to `NaN`. * * expect('foo').to.equal('foo'); // Recommended * expect('foo').to.not.be.NaN; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(42, 'nooo why fail??').to.be.NaN; * * @name NaN * @namespace BDD * @api public */ Assertion.addProperty('NaN', function () { this.assert( _.isNaN(flag(this, 'object')) , 'expected #{this} to be NaN' , 'expected #{this} not to be NaN' ); }); /** * ### .exist * * Asserts that the target is not strictly (`===`) equal to either `null` or * `undefined`. However, it's often best to assert that the target is equal to * its expected value. * * expect(1).to.equal(1); // Recommended * expect(1).to.exist; // Not recommended * * expect(0).to.equal(0); // Recommended * expect(0).to.exist; // Not recommended * * Add `.not` earlier in the chain to negate `.exist`. * * expect(null).to.be.null; // Recommended * expect(null).to.not.exist; // Not recommended * * expect(undefined).to.be.undefined; // Recommended * expect(undefined).to.not.exist; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect(null, 'nooo why fail??').to.exist; * * @name exist * @namespace BDD * @api public */ Assertion.addProperty('exist', function () { var val = flag(this, 'object'); this.assert( val !== null && val !== undefined , 'expected #{this} to exist' , 'expected #{this} to not exist' ); }); /** * ### .empty * * When the target is a string or array, `.empty` asserts that the target's * `length` property is strictly (`===`) equal to `0`. * * expect([]).to.be.empty; * expect('').to.be.empty; * * When the target is a map or set, `.empty` asserts that the target's `size` * property is strictly equal to `0`. * * expect(new Set()).to.be.empty; * expect(new Map()).to.be.empty; * * When the target is a non-function object, `.empty` asserts that the target * doesn't have any own enumerable properties. Properties with Symbol-based * keys are excluded from the count. * * expect({}).to.be.empty; * * Because `.empty` does different things based on the target's type, it's * important to check the target's type before using `.empty`. See the `.a` * doc for info on testing a target's type. * * expect([]).to.be.an('array').that.is.empty; * * Add `.not` earlier in the chain to negate `.empty`. However, it's often * best to assert that the target contains its expected number of values, * rather than asserting that it's not empty. * * expect([1, 2, 3]).to.have.lengthOf(3); // Recommended * expect([1, 2, 3]).to.not.be.empty; // Not recommended * * expect(new Set([1, 2, 3])).to.have.property('size', 3); // Recommended * expect(new Set([1, 2, 3])).to.not.be.empty; // Not recommended * * expect(Object.keys({a: 1})).to.have.lengthOf(1); // Recommended * expect({a: 1}).to.not.be.empty; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect([1, 2, 3], 'nooo why fail??').to.be.empty; * * @name empty * @namespace BDD * @api public */ Assertion.addProperty('empty', function () { var val = flag(this, 'object') , ssfi = flag(this, 'ssfi') , flagMsg = flag(this, 'message') , itemsCount; flagMsg = flagMsg ? flagMsg + ': ' : ''; switch (_.type(val).toLowerCase()) { case 'array': case 'string': itemsCount = val.length; break; case 'map': case 'set': itemsCount = val.size; break; case 'weakmap': case 'weakset': throw new AssertionError( flagMsg + '.empty was passed a weak collection', undefined, ssfi ); case 'function': var msg = flagMsg + '.empty was passed a function ' + _.getName(val); throw new AssertionError(msg.trim(), undefined, ssfi); default: if (val !== Object(val)) { throw new AssertionError( flagMsg + '.empty was passed non-string primitive ' + _.inspect(val), undefined, ssfi ); } itemsCount = Object.keys(val).length; } this.assert( 0 === itemsCount , 'expected #{this} to be empty' , 'expected #{this} not to be empty' ); }); /** * ### .arguments * * Asserts that the target is an `arguments` object. * * function test () { * expect(arguments).to.be.arguments; * } * * test(); * * Add `.not` earlier in the chain to negate `.arguments`. However, it's often * best to assert which type the target is expected to be, rather than * asserting that its not an `arguments` object. * * expect('foo').to.be.a('string'); // Recommended * expect('foo').to.not.be.arguments; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect({}, 'nooo why fail??').to.be.arguments; * * The alias `.Arguments` can be used interchangeably with `.arguments`. * * @name arguments * @alias Arguments * @namespace BDD * @api public */ function checkArguments () { var obj = flag(this, 'object') , type = _.type(obj); this.assert( 'Arguments' === type , 'expected #{this} to be arguments but got ' + type , 'expected #{this} to not be arguments' ); } Assertion.addProperty('arguments', checkArguments); Assertion.addProperty('Arguments', checkArguments); /** * ### .equal(val[, msg]) * * Asserts that the target is strictly (`===`) equal to the given `val`. * * expect(1).to.equal(1); * expect('foo').to.equal('foo'); * * Add `.deep` earlier in the chain to use deep equality instead. See the * `deep-eql` project page for info on the deep equality algorithm: * https://github.com/chaijs/deep-eql. * * // Target object deeply (but not strictly) equals `{a: 1}` * expect({a: 1}).to.deep.equal({a: 1}); * expect({a: 1}).to.not.equal({a: 1}); * * // Target array deeply (but not strictly) equals `[1, 2]` * expect([1, 2]).to.deep.equal([1, 2]); * expect([1, 2]).to.not.equal([1, 2]); * * Add `.not` earlier in the chain to negate `.equal`. However, it's often * best to assert that the target is equal to its expected value, rather than * not equal to one of countless unexpected values. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.equal(2); // Not recommended * * `.equal` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(1).to.equal(2, 'nooo why fail??'); * expect(1, 'nooo why fail??').to.equal(2); * * The aliases `.equals` and `eq` can be used interchangeably with `.equal`. * * @name equal * @alias equals * @alias eq * @param {Mixed} val * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertEqual (val, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object'); if (flag(this, 'deep')) { var prevLockSsfi = flag(this, 'lockSsfi'); flag(this, 'lockSsfi', true); this.eql(val); flag(this, 'lockSsfi', prevLockSsfi); } else { this.assert( val === obj , 'expected #{this} to equal #{exp}' , 'expected #{this} to not equal #{exp}' , val , this._obj , true ); } } Assertion.addMethod('equal', assertEqual); Assertion.addMethod('equals', assertEqual); Assertion.addMethod('eq', assertEqual); /** * ### .eql(obj[, msg]) * * Asserts that the target is deeply equal to the given `obj`. See the * `deep-eql` project page for info on the deep equality algorithm: * https://github.com/chaijs/deep-eql. * * // Target object is deeply (but not strictly) equal to {a: 1} * expect({a: 1}).to.eql({a: 1}).but.not.equal({a: 1}); * * // Target array is deeply (but not strictly) equal to [1, 2] * expect([1, 2]).to.eql([1, 2]).but.not.equal([1, 2]); * * Add `.not` earlier in the chain to negate `.eql`. However, it's often best * to assert that the target is deeply equal to its expected value, rather * than not deeply equal to one of countless unexpected values. * * expect({a: 1}).to.eql({a: 1}); // Recommended * expect({a: 1}).to.not.eql({b: 2}); // Not recommended * * `.eql` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect({a: 1}).to.eql({b: 2}, 'nooo why fail??'); * expect({a: 1}, 'nooo why fail??').to.eql({b: 2}); * * The alias `.eqls` can be used interchangeably with `.eql`. * * The `.deep.equal` assertion is almost identical to `.eql` but with one * difference: `.deep.equal` causes deep equality comparisons to also be used * for any other assertions that follow in the chain. * * @name eql * @alias eqls * @param {Mixed} obj * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertEql(obj, msg) { if (msg) flag(this, 'message', msg); this.assert( _.eql(obj, flag(this, 'object')) , 'expected #{this} to deeply equal #{exp}' , 'expected #{this} to not deeply equal #{exp}' , obj , this._obj , true ); } Assertion.addMethod('eql', assertEql); Assertion.addMethod('eqls', assertEql); /** * ### .above(n[, msg]) * * Asserts that the target is a number or a date greater than the given number or date `n` respectively. * However, it's often best to assert that the target is equal to its expected * value. * * expect(2).to.equal(2); // Recommended * expect(2).to.be.above(1); // Not recommended * * Add `.lengthOf` earlier in the chain to assert that the target's `length` * or `size` is greater than the given number `n`. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.have.lengthOf.above(2); // Not recommended * * expect([1, 2, 3]).to.have.lengthOf(3); // Recommended * expect([1, 2, 3]).to.have.lengthOf.above(2); // Not recommended * * Add `.not` earlier in the chain to negate `.above`. * * expect(2).to.equal(2); // Recommended * expect(1).to.not.be.above(2); // Not recommended * * `.above` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(1).to.be.above(2, 'nooo why fail??'); * expect(1, 'nooo why fail??').to.be.above(2); * * The aliases `.gt` and `.greaterThan` can be used interchangeably with * `.above`. * * @name above * @alias gt * @alias greaterThan * @param {Number} n * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertAbove (n, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , doLength = flag(this, 'doLength') , flagMsg = flag(this, 'message') , msgPrefix = ((flagMsg) ? flagMsg + ': ' : '') , ssfi = flag(this, 'ssfi') , objType = _.type(obj).toLowerCase() , nType = _.type(n).toLowerCase() , errorMessage , shouldThrow = true; if (doLength && objType !== 'map' && objType !== 'set') { new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); } if (!doLength && (objType === 'date' && nType !== 'date')) { errorMessage = msgPrefix + 'the argument to above must be a date'; } else if (nType !== 'number' && (doLength || objType === 'number')) { errorMessage = msgPrefix + 'the argument to above must be a number'; } else if (!doLength && (objType !== 'date' && objType !== 'number')) { var printObj = (objType === 'string') ? "'" + obj + "'" : obj; errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date'; } else { shouldThrow = false; } if (shouldThrow) { throw new AssertionError(errorMessage, undefined, ssfi); } if (doLength) { var descriptor = 'length' , itemsCount; if (objType === 'map' || objType === 'set') { descriptor = 'size'; itemsCount = obj.size; } else { itemsCount = obj.length; } this.assert( itemsCount > n , 'expected #{this} to have a ' + descriptor + ' above #{exp} but got #{act}' , 'expected #{this} to not have a ' + descriptor + ' above #{exp}' , n , itemsCount ); } else { this.assert( obj > n , 'expected #{this} to be above #{exp}' , 'expected #{this} to be at most #{exp}' , n ); } } Assertion.addMethod('above', assertAbove); Assertion.addMethod('gt', assertAbove); Assertion.addMethod('greaterThan', assertAbove); /** * ### .least(n[, msg]) * * Asserts that the target is a number or a date greater than or equal to the given * number or date `n` respectively. However, it's often best to assert that the target is equal to * its expected value. * * expect(2).to.equal(2); // Recommended * expect(2).to.be.at.least(1); // Not recommended * expect(2).to.be.at.least(2); // Not recommended * * Add `.lengthOf` earlier in the chain to assert that the target's `length` * or `size` is greater than or equal to the given number `n`. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.have.lengthOf.at.least(2); // Not recommended * * expect([1, 2, 3]).to.have.lengthOf(3); // Recommended * expect([1, 2, 3]).to.have.lengthOf.at.least(2); // Not recommended * * Add `.not` earlier in the chain to negate `.least`. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.at.least(2); // Not recommended * * `.least` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(1).to.be.at.least(2, 'nooo why fail??'); * expect(1, 'nooo why fail??').to.be.at.least(2); * * The alias `.gte` can be used interchangeably with `.least`. * * @name least * @alias gte * @param {Number} n * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertLeast (n, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , doLength = flag(this, 'doLength') , flagMsg = flag(this, 'message') , msgPrefix = ((flagMsg) ? flagMsg + ': ' : '') , ssfi = flag(this, 'ssfi') , objType = _.type(obj).toLowerCase() , nType = _.type(n).toLowerCase() , errorMessage , shouldThrow = true; if (doLength && objType !== 'map' && objType !== 'set') { new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); } if (!doLength && (objType === 'date' && nType !== 'date')) { errorMessage = msgPrefix + 'the argument to least must be a date'; } else if (nType !== 'number' && (doLength || objType === 'number')) { errorMessage = msgPrefix + 'the argument to least must be a number'; } else if (!doLength && (objType !== 'date' && objType !== 'number')) { var printObj = (objType === 'string') ? "'" + obj + "'" : obj; errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date'; } else { shouldThrow = false; } if (shouldThrow) { throw new AssertionError(errorMessage, undefined, ssfi); } if (doLength) { var descriptor = 'length' , itemsCount; if (objType === 'map' || objType === 'set') { descriptor = 'size'; itemsCount = obj.size; } else { itemsCount = obj.length; } this.assert( itemsCount >= n , 'expected #{this} to have a ' + descriptor + ' at least #{exp} but got #{act}' , 'expected #{this} to have a ' + descriptor + ' below #{exp}' , n , itemsCount ); } else { this.assert( obj >= n , 'expected #{this} to be at least #{exp}' , 'expected #{this} to be below #{exp}' , n ); } } Assertion.addMethod('least', assertLeast); Assertion.addMethod('gte', assertLeast); /** * ### .below(n[, msg]) * * Asserts that the target is a number or a date less than the given number or date `n` respectively. * However, it's often best to assert that the target is equal to its expected * value. * * expect(1).to.equal(1); // Recommended * expect(1).to.be.below(2); // Not recommended * * Add `.lengthOf` earlier in the chain to assert that the target's `length` * or `size` is less than the given number `n`. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.have.lengthOf.below(4); // Not recommended * * expect([1, 2, 3]).to.have.length(3); // Recommended * expect([1, 2, 3]).to.have.lengthOf.below(4); // Not recommended * * Add `.not` earlier in the chain to negate `.below`. * * expect(2).to.equal(2); // Recommended * expect(2).to.not.be.below(1); // Not recommended * * `.below` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(2).to.be.below(1, 'nooo why fail??'); * expect(2, 'nooo why fail??').to.be.below(1); * * The aliases `.lt` and `.lessThan` can be used interchangeably with * `.below`. * * @name below * @alias lt * @alias lessThan * @param {Number} n * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertBelow (n, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , doLength = flag(this, 'doLength') , flagMsg = flag(this, 'message') , msgPrefix = ((flagMsg) ? flagMsg + ': ' : '') , ssfi = flag(this, 'ssfi') , objType = _.type(obj).toLowerCase() , nType = _.type(n).toLowerCase() , errorMessage , shouldThrow = true; if (doLength && objType !== 'map' && objType !== 'set') { new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); } if (!doLength && (objType === 'date' && nType !== 'date')) { errorMessage = msgPrefix + 'the argument to below must be a date'; } else if (nType !== 'number' && (doLength || objType === 'number')) { errorMessage = msgPrefix + 'the argument to below must be a number'; } else if (!doLength && (objType !== 'date' && objType !== 'number')) { var printObj = (objType === 'string') ? "'" + obj + "'" : obj; errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date'; } else { shouldThrow = false; } if (shouldThrow) { throw new AssertionError(errorMessage, undefined, ssfi); } if (doLength) { var descriptor = 'length' , itemsCount; if (objType === 'map' || objType === 'set') { descriptor = 'size'; itemsCount = obj.size; } else { itemsCount = obj.length; } this.assert( itemsCount < n , 'expected #{this} to have a ' + descriptor + ' below #{exp} but got #{act}' , 'expected #{this} to not have a ' + descriptor + ' below #{exp}' , n , itemsCount ); } else { this.assert( obj < n , 'expected #{this} to be below #{exp}' , 'expected #{this} to be at least #{exp}' , n ); } } Assertion.addMethod('below', assertBelow); Assertion.addMethod('lt', assertBelow); Assertion.addMethod('lessThan', assertBelow); /** * ### .most(n[, msg]) * * Asserts that the target is a number or a date less than or equal to the given number * or date `n` respectively. However, it's often best to assert that the target is equal to its * expected value. * * expect(1).to.equal(1); // Recommended * expect(1).to.be.at.most(2); // Not recommended * expect(1).to.be.at.most(1); // Not recommended * * Add `.lengthOf` earlier in the chain to assert that the target's `length` * or `size` is less than or equal to the given number `n`. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.have.lengthOf.at.most(4); // Not recommended * * expect([1, 2, 3]).to.have.lengthOf(3); // Recommended * expect([1, 2, 3]).to.have.lengthOf.at.most(4); // Not recommended * * Add `.not` earlier in the chain to negate `.most`. * * expect(2).to.equal(2); // Recommended * expect(2).to.not.be.at.most(1); // Not recommended * * `.most` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(2).to.be.at.most(1, 'nooo why fail??'); * expect(2, 'nooo why fail??').to.be.at.most(1); * * The alias `.lte` can be used interchangeably with `.most`. * * @name most * @alias lte * @param {Number} n * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertMost (n, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , doLength = flag(this, 'doLength') , flagMsg = flag(this, 'message') , msgPrefix = ((flagMsg) ? flagMsg + ': ' : '') , ssfi = flag(this, 'ssfi') , objType = _.type(obj).toLowerCase() , nType = _.type(n).toLowerCase() , errorMessage , shouldThrow = true; if (doLength && objType !== 'map' && objType !== 'set') { new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); } if (!doLength && (objType === 'date' && nType !== 'date')) { errorMessage = msgPrefix + 'the argument to most must be a date'; } else if (nType !== 'number' && (doLength || objType === 'number')) { errorMessage = msgPrefix + 'the argument to most must be a number'; } else if (!doLength && (objType !== 'date' && objType !== 'number')) { var printObj = (objType === 'string') ? "'" + obj + "'" : obj; errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date'; } else { shouldThrow = false; } if (shouldThrow) { throw new AssertionError(errorMessage, undefined, ssfi); } if (doLength) { var descriptor = 'length' , itemsCount; if (objType === 'map' || objType === 'set') { descriptor = 'size'; itemsCount = obj.size; } else { itemsCount = obj.length; } this.assert( itemsCount <= n , 'expected #{this} to have a ' + descriptor + ' at most #{exp} but got #{act}' , 'expected #{this} to have a ' + descriptor + ' above #{exp}' , n , itemsCount ); } else { this.assert( obj <= n , 'expected #{this} to be at most #{exp}' , 'expected #{this} to be above #{exp}' , n ); } } Assertion.addMethod('most', assertMost); Assertion.addMethod('lte', assertMost); /** * ### .within(start, finish[, msg]) * * Asserts that the target is a number or a date greater than or equal to the given * number or date `start`, and less than or equal to the given number or date `finish` respectively. * However, it's often best to assert that the target is equal to its expected * value. * * expect(2).to.equal(2); // Recommended * expect(2).to.be.within(1, 3); // Not recommended * expect(2).to.be.within(2, 3); // Not recommended * expect(2).to.be.within(1, 2); // Not recommended * * Add `.lengthOf` earlier in the chain to assert that the target's `length` * or `size` is greater than or equal to the given number `start`, and less * than or equal to the given number `finish`. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.have.lengthOf.within(2, 4); // Not recommended * * expect([1, 2, 3]).to.have.lengthOf(3); // Recommended * expect([1, 2, 3]).to.have.lengthOf.within(2, 4); // Not recommended * * Add `.not` earlier in the chain to negate `.within`. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.within(2, 4); // Not recommended * * `.within` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect(4).to.be.within(1, 3, 'nooo why fail??'); * expect(4, 'nooo why fail??').to.be.within(1, 3); * * @name within * @param {Number} start lower bound inclusive * @param {Number} finish upper bound inclusive * @param {String} msg _optional_ * @namespace BDD * @api public */ Assertion.addMethod('within', function (start, finish, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , doLength = flag(this, 'doLength') , flagMsg = flag(this, 'message') , msgPrefix = ((flagMsg) ? flagMsg + ': ' : '') , ssfi = flag(this, 'ssfi') , objType = _.type(obj).toLowerCase() , startType = _.type(start).toLowerCase() , finishType = _.type(finish).toLowerCase() , errorMessage , shouldThrow = true , range = (startType === 'date' && finishType === 'date') ? start.toUTCString() + '..' + finish.toUTCString() : start + '..' + finish; if (doLength && objType !== 'map' && objType !== 'set') { new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); } if (!doLength && (objType === 'date' && (startType !== 'date' || finishType !== 'date'))) { errorMessage = msgPrefix + 'the arguments to within must be dates'; } else if ((startType !== 'number' || finishType !== 'number') && (doLength || objType === 'number')) { errorMessage = msgPrefix + 'the arguments to within must be numbers'; } else if (!doLength && (objType !== 'date' && objType !== 'number')) { var printObj = (objType === 'string') ? "'" + obj + "'" : obj; errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date'; } else { shouldThrow = false; } if (shouldThrow) { throw new AssertionError(errorMessage, undefined, ssfi); } if (doLength) { var descriptor = 'length' , itemsCount; if (objType === 'map' || objType === 'set') { descriptor = 'size'; itemsCount = obj.size; } else { itemsCount = obj.length; } this.assert( itemsCount >= start && itemsCount <= finish , 'expected #{this} to have a ' + descriptor + ' within ' + range , 'expected #{this} to not have a ' + descriptor + ' within ' + range ); } else { this.assert( obj >= start && obj <= finish , 'expected #{this} to be within ' + range , 'expected #{this} to not be within ' + range ); } }); /** * ### .instanceof(constructor[, msg]) * * Asserts that the target is an instance of the given `constructor`. * * function Cat () { } * * expect(new Cat()).to.be.an.instanceof(Cat); * expect([1, 2]).to.be.an.instanceof(Array); * * Add `.not` earlier in the chain to negate `.instanceof`. * * expect({a: 1}).to.not.be.an.instanceof(Array); * * `.instanceof` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect(1).to.be.an.instanceof(Array, 'nooo why fail??'); * expect(1, 'nooo why fail??').to.be.an.instanceof(Array); * * Due to limitations in ES5, `.instanceof` may not always work as expected * when using a transpiler such as Babel or TypeScript. In particular, it may * produce unexpected results when subclassing built-in object such as * `Array`, `Error`, and `Map`. See your transpiler's docs for details: * * - ([Babel](https://babeljs.io/docs/usage/caveats/#classes)) * - ([TypeScript](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work)) * * The alias `.instanceOf` can be used interchangeably with `.instanceof`. * * @name instanceof * @param {Constructor} constructor * @param {String} msg _optional_ * @alias instanceOf * @namespace BDD * @api public */ function assertInstanceOf (constructor, msg) { if (msg) flag(this, 'message', msg); var target = flag(this, 'object') var ssfi = flag(this, 'ssfi'); var flagMsg = flag(this, 'message'); try { var isInstanceOf = target instanceof constructor; } catch (err) { if (err instanceof TypeError) { flagMsg = flagMsg ? flagMsg + ': ' : ''; throw new AssertionError( flagMsg + 'The instanceof assertion needs a constructor but ' + _.type(constructor) + ' was given.', undefined, ssfi ); } throw err; } var name = _.getName(constructor); if (name === null) { name = 'an unnamed constructor'; } this.assert( isInstanceOf , 'expected #{this} to be an instance of ' + name , 'expected #{this} to not be an instance of ' + name ); }; Assertion.addMethod('instanceof', assertInstanceOf); Assertion.addMethod('instanceOf', assertInstanceOf); /** * ### .property(name[, val[, msg]]) * * Asserts that the target has a property with the given key `name`. * * expect({a: 1}).to.have.property('a'); * * When `val` is provided, `.property` also asserts that the property's value * is equal to the given `val`. * * expect({a: 1}).to.have.property('a', 1); * * By default, strict (`===`) equality is used. Add `.deep` earlier in the * chain to use deep equality instead. See the `deep-eql` project page for * info on the deep equality algorithm: https://github.com/chaijs/deep-eql. * * // Target object deeply (but not strictly) has property `x: {a: 1}` * expect({x: {a: 1}}).to.have.deep.property('x', {a: 1}); * expect({x: {a: 1}}).to.not.have.property('x', {a: 1}); * * The target's enumerable and non-enumerable properties are always included * in the search. By default, both own and inherited properties are included. * Add `.own` earlier in the chain to exclude inherited properties from the * search. * * Object.prototype.b = 2; * * expect({a: 1}).to.have.own.property('a'); * expect({a: 1}).to.have.own.property('a', 1); * expect({a: 1}).to.have.property('b'); * expect({a: 1}).to.not.have.own.property('b'); * * `.deep` and `.own` can be combined. * * expect({x: {a: 1}}).to.have.deep.own.property('x', {a: 1}); * * Add `.nested` earlier in the chain to enable dot- and bracket-notation when * referencing nested properties. * * expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]'); * expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]', 'y'); * * If `.` or `[]` are part of an actual property name, they can be escaped by * adding two backslashes before them. * * expect({'.a': {'[b]': 'x'}}).to.have.nested.property('\\.a.\\[b\\]'); * * `.deep` and `.nested` can be combined. * * expect({a: {b: [{c: 3}]}}) * .to.have.deep.nested.property('a.b[0]', {c: 3}); * * `.own` and `.nested` cannot be combined. * * Add `.not` earlier in the chain to negate `.property`. * * expect({a: 1}).to.not.have.property('b'); * * However, it's dangerous to negate `.property` when providing `val`. The * problem is that it creates uncertain expectations by asserting that the * target either doesn't have a property with the given key `name`, or that it * does have a property with the given key `name` but its value isn't equal to * the given `val`. It's often best to identify the exact output that's * expected, and then write an assertion that only accepts that exact output. * * When the target isn't expected to have a property with the given key * `name`, it's often best to assert exactly that. * * expect({b: 2}).to.not.have.property('a'); // Recommended * expect({b: 2}).to.not.have.property('a', 1); // Not recommended * * When the target is expected to have a property with the given key `name`, * it's often best to assert that the property has its expected value, rather * than asserting that it doesn't have one of many unexpected values. * * expect({a: 3}).to.have.property('a', 3); // Recommended * expect({a: 3}).to.not.have.property('a', 1); // Not recommended * * `.property` changes the target of any assertions that follow in the chain * to be the value of the property from the original target object. * * expect({a: 1}).to.have.property('a').that.is.a('number'); * * `.property` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. When not providing `val`, only use the * second form. * * // Recommended * expect({a: 1}).to.have.property('a', 2, 'nooo why fail??'); * expect({a: 1}, 'nooo why fail??').to.have.property('a', 2); * expect({a: 1}, 'nooo why fail??').to.have.property('b'); * * // Not recommended * expect({a: 1}).to.have.property('b', undefined, 'nooo why fail??'); * * The above assertion isn't the same thing as not providing `val`. Instead, * it's asserting that the target object has a `b` property that's equal to * `undefined`. * * The assertions `.ownProperty` and `.haveOwnProperty` can be used * interchangeably with `.own.property`. * * @name property * @param {String} name * @param {Mixed} val (optional) * @param {String} msg _optional_ * @returns value of property for chaining * @namespace BDD * @api public */ function assertProperty (name, val, msg) { if (msg) flag(this, 'message', msg); var isNested = flag(this, 'nested') , isOwn = flag(this, 'own') , flagMsg = flag(this, 'message') , obj = flag(this, 'object') , ssfi = flag(this, 'ssfi') , nameType = typeof name; flagMsg = flagMsg ? flagMsg + ': ' : ''; if (isNested) { if (nameType !== 'string') { throw new AssertionError( flagMsg + 'the argument to property must be a string when using nested syntax', undefined, ssfi ); } } else { if (nameType !== 'string' && nameType !== 'number' && nameType !== 'symbol') { throw new AssertionError( flagMsg + 'the argument to property must be a string, number, or symbol', undefined, ssfi ); } } if (isNested && isOwn) { throw new AssertionError( flagMsg + 'The "nested" and "own" flags cannot be combined.', undefined, ssfi ); } if (obj === null || obj === undefined) { throw new AssertionError( flagMsg + 'Target cannot be null or undefined.', undefined, ssfi ); } var isDeep = flag(this, 'deep') , negate = flag(this, 'negate') , pathInfo = isNested ? _.getPathInfo(obj, name) : null , value = isNested ? pathInfo.value : obj[name]; var descriptor = ''; if (isDeep) descriptor += 'deep '; if (isOwn) descriptor += 'own '; if (isNested) descriptor += 'nested '; descriptor += 'property '; var hasProperty; if (isOwn) hasProperty = Object.prototype.hasOwnProperty.call(obj, name); else if (isNested) hasProperty = pathInfo.exists; else hasProperty = _.hasProperty(obj, name); // When performing a negated assertion for both name and val, merely having // a property with the given name isn't enough to cause the assertion to // fail. It must both have a property with the given name, and the value of // that property must equal the given val. Therefore, skip this assertion in // favor of the next. if (!negate || arguments.length === 1) { this.assert( hasProperty , 'expected #{this} to have ' + descriptor + _.inspect(name) , 'expected #{this} to not have ' + descriptor + _.inspect(name)); } if (arguments.length > 1) { this.assert( hasProperty && (isDeep ? _.eql(val, value) : val === value) , 'expected #{this} to have ' + descriptor + _.inspect(name) + ' of #{exp}, but got #{act}' , 'expected #{this} to not have ' + descriptor + _.inspect(name) + ' of #{act}' , val , value ); } flag(this, 'object', value); } Assertion.addMethod('property', assertProperty); function assertOwnProperty (name, value, msg) { flag(this, 'own', true); assertProperty.apply(this, arguments); } Assertion.addMethod('ownProperty', assertOwnProperty); Assertion.addMethod('haveOwnProperty', assertOwnProperty); /** * ### .ownPropertyDescriptor(name[, descriptor[, msg]]) * * Asserts that the target has its own property descriptor with the given key * `name`. Enumerable and non-enumerable properties are included in the * search. * * expect({a: 1}).to.have.ownPropertyDescriptor('a'); * * When `descriptor` is provided, `.ownPropertyDescriptor` also asserts that * the property's descriptor is deeply equal to the given `descriptor`. See * the `deep-eql` project page for info on the deep equality algorithm: * https://github.com/chaijs/deep-eql. * * expect({a: 1}).to.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 1, * }); * * Add `.not` earlier in the chain to negate `.ownPropertyDescriptor`. * * expect({a: 1}).to.not.have.ownPropertyDescriptor('b'); * * However, it's dangerous to negate `.ownPropertyDescriptor` when providing * a `descriptor`. The problem is that it creates uncertain expectations by * asserting that the target either doesn't have a property descriptor with * the given key `name`, or that it does have a property descriptor with the * given key `name` but its not deeply equal to the given `descriptor`. It's * often best to identify the exact output that's expected, and then write an * assertion that only accepts that exact output. * * When the target isn't expected to have a property descriptor with the given * key `name`, it's often best to assert exactly that. * * // Recommended * expect({b: 2}).to.not.have.ownPropertyDescriptor('a'); * * // Not recommended * expect({b: 2}).to.not.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 1, * }); * * When the target is expected to have a property descriptor with the given * key `name`, it's often best to assert that the property has its expected * descriptor, rather than asserting that it doesn't have one of many * unexpected descriptors. * * // Recommended * expect({a: 3}).to.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 3, * }); * * // Not recommended * expect({a: 3}).to.not.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 1, * }); * * `.ownPropertyDescriptor` changes the target of any assertions that follow * in the chain to be the value of the property descriptor from the original * target object. * * expect({a: 1}).to.have.ownPropertyDescriptor('a') * .that.has.property('enumerable', true); * * `.ownPropertyDescriptor` accepts an optional `msg` argument which is a * custom error message to show when the assertion fails. The message can also * be given as the second argument to `expect`. When not providing * `descriptor`, only use the second form. * * // Recommended * expect({a: 1}).to.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 2, * }, 'nooo why fail??'); * * // Recommended * expect({a: 1}, 'nooo why fail??').to.have.ownPropertyDescriptor('a', { * configurable: true, * enumerable: true, * writable: true, * value: 2, * }); * * // Recommended * expect({a: 1}, 'nooo why fail??').to.have.ownPropertyDescriptor('b'); * * // Not recommended * expect({a: 1}) * .to.have.ownPropertyDescriptor('b', undefined, 'nooo why fail??'); * * The above assertion isn't the same thing as not providing `descriptor`. * Instead, it's asserting that the target object has a `b` property * descriptor that's deeply equal to `undefined`. * * The alias `.haveOwnPropertyDescriptor` can be used interchangeably with * `.ownPropertyDescriptor`. * * @name ownPropertyDescriptor * @alias haveOwnPropertyDescriptor * @param {String} name * @param {Object} descriptor _optional_ * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertOwnPropertyDescriptor (name, descriptor, msg) { if (typeof descriptor === 'string') { msg = descriptor; descriptor = null; } if (msg) flag(this, 'message', msg); var obj = flag(this, 'object'); var actualDescriptor = Object.getOwnPropertyDescriptor(Object(obj), name); if (actualDescriptor && descriptor) { this.assert( _.eql(descriptor, actualDescriptor) , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to match ' + _.inspect(descriptor) + ', got ' + _.inspect(actualDescriptor) , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to not match ' + _.inspect(descriptor) , descriptor , actualDescriptor , true ); } else { this.assert( actualDescriptor , 'expected #{this} to have an own property descriptor for ' + _.inspect(name) , 'expected #{this} to not have an own property descriptor for ' + _.inspect(name) ); } flag(this, 'object', actualDescriptor); } Assertion.addMethod('ownPropertyDescriptor', assertOwnPropertyDescriptor); Assertion.addMethod('haveOwnPropertyDescriptor', assertOwnPropertyDescriptor); /** * ### .lengthOf(n[, msg]) * * Asserts that the target's `length` or `size` is equal to the given number * `n`. * * expect([1, 2, 3]).to.have.lengthOf(3); * expect('foo').to.have.lengthOf(3); * expect(new Set([1, 2, 3])).to.have.lengthOf(3); * expect(new Map([['a', 1], ['b', 2], ['c', 3]])).to.have.lengthOf(3); * * Add `.not` earlier in the chain to negate `.lengthOf`. However, it's often * best to assert that the target's `length` property is equal to its expected * value, rather than not equal to one of many unexpected values. * * expect('foo').to.have.lengthOf(3); // Recommended * expect('foo').to.not.have.lengthOf(4); // Not recommended * * `.lengthOf` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect([1, 2, 3]).to.have.lengthOf(2, 'nooo why fail??'); * expect([1, 2, 3], 'nooo why fail??').to.have.lengthOf(2); * * `.lengthOf` can also be used as a language chain, causing all `.above`, * `.below`, `.least`, `.most`, and `.within` assertions that follow in the * chain to use the target's `length` property as the target. However, it's * often best to assert that the target's `length` property is equal to its * expected length, rather than asserting that its `length` property falls * within some range of values. * * // Recommended * expect([1, 2, 3]).to.have.lengthOf(3); * * // Not recommended * expect([1, 2, 3]).to.have.lengthOf.above(2); * expect([1, 2, 3]).to.have.lengthOf.below(4); * expect([1, 2, 3]).to.have.lengthOf.at.least(3); * expect([1, 2, 3]).to.have.lengthOf.at.most(3); * expect([1, 2, 3]).to.have.lengthOf.within(2,4); * * Due to a compatibility issue, the alias `.length` can't be chained directly * off of an uninvoked method such as `.a`. Therefore, `.length` can't be used * interchangeably with `.lengthOf` in every situation. It's recommended to * always use `.lengthOf` instead of `.length`. * * expect([1, 2, 3]).to.have.a.length(3); // incompatible; throws error * expect([1, 2, 3]).to.have.a.lengthOf(3); // passes as expected * * @name lengthOf * @alias length * @param {Number} n * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertLengthChain () { flag(this, 'doLength', true); } function assertLength (n, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , objType = _.type(obj).toLowerCase() , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi') , descriptor = 'length' , itemsCount; switch (objType) { case 'map': case 'set': descriptor = 'size'; itemsCount = obj.size; break; default: new Assertion(obj, flagMsg, ssfi, true).to.have.property('length'); itemsCount = obj.length; } this.assert( itemsCount == n , 'expected #{this} to have a ' + descriptor + ' of #{exp} but got #{act}' , 'expected #{this} to not have a ' + descriptor + ' of #{act}' , n , itemsCount ); } Assertion.addChainableMethod('length', assertLength, assertLengthChain); Assertion.addChainableMethod('lengthOf', assertLength, assertLengthChain); /** * ### .match(re[, msg]) * * Asserts that the target matches the given regular expression `re`. * * expect('foobar').to.match(/^foo/); * * Add `.not` earlier in the chain to negate `.match`. * * expect('foobar').to.not.match(/taco/); * * `.match` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect('foobar').to.match(/taco/, 'nooo why fail??'); * expect('foobar', 'nooo why fail??').to.match(/taco/); * * The alias `.matches` can be used interchangeably with `.match`. * * @name match * @alias matches * @param {RegExp} re * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertMatch(re, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object'); this.assert( re.exec(obj) , 'expected #{this} to match ' + re , 'expected #{this} not to match ' + re ); } Assertion.addMethod('match', assertMatch); Assertion.addMethod('matches', assertMatch); /** * ### .string(str[, msg]) * * Asserts that the target string contains the given substring `str`. * * expect('foobar').to.have.string('bar'); * * Add `.not` earlier in the chain to negate `.string`. * * expect('foobar').to.not.have.string('taco'); * * `.string` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect('foobar').to.have.string('taco', 'nooo why fail??'); * expect('foobar', 'nooo why fail??').to.have.string('taco'); * * @name string * @param {String} str * @param {String} msg _optional_ * @namespace BDD * @api public */ Assertion.addMethod('string', function (str, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(obj, flagMsg, ssfi, true).is.a('string'); this.assert( ~obj.indexOf(str) , 'expected #{this} to contain ' + _.inspect(str) , 'expected #{this} to not contain ' + _.inspect(str) ); }); /** * ### .keys(key1[, key2[, ...]]) * * Asserts that the target object, array, map, or set has the given keys. Only * the target's own inherited properties are included in the search. * * When the target is an object or array, keys can be provided as one or more * string arguments, a single array argument, or a single object argument. In * the latter case, only the keys in the given object matter; the values are * ignored. * * expect({a: 1, b: 2}).to.have.all.keys('a', 'b'); * expect(['x', 'y']).to.have.all.keys(0, 1); * * expect({a: 1, b: 2}).to.have.all.keys(['a', 'b']); * expect(['x', 'y']).to.have.all.keys([0, 1]); * * expect({a: 1, b: 2}).to.have.all.keys({a: 4, b: 5}); // ignore 4 and 5 * expect(['x', 'y']).to.have.all.keys({0: 4, 1: 5}); // ignore 4 and 5 * * When the target is a map or set, each key must be provided as a separate * argument. * * expect(new Map([['a', 1], ['b', 2]])).to.have.all.keys('a', 'b'); * expect(new Set(['a', 'b'])).to.have.all.keys('a', 'b'); * * Because `.keys` does different things based on the target's type, it's * important to check the target's type before using `.keys`. See the `.a` doc * for info on testing a target's type. * * expect({a: 1, b: 2}).to.be.an('object').that.has.all.keys('a', 'b'); * * By default, strict (`===`) equality is used to compare keys of maps and * sets. Add `.deep` earlier in the chain to use deep equality instead. See * the `deep-eql` project page for info on the deep equality algorithm: * https://github.com/chaijs/deep-eql. * * // Target set deeply (but not strictly) has key `{a: 1}` * expect(new Set([{a: 1}])).to.have.all.deep.keys([{a: 1}]); * expect(new Set([{a: 1}])).to.not.have.all.keys([{a: 1}]); * * By default, the target must have all of the given keys and no more. Add * `.any` earlier in the chain to only require that the target have at least * one of the given keys. Also, add `.not` earlier in the chain to negate * `.keys`. It's often best to add `.any` when negating `.keys`, and to use * `.all` when asserting `.keys` without negation. * * When negating `.keys`, `.any` is preferred because `.not.any.keys` asserts * exactly what's expected of the output, whereas `.not.all.keys` creates * uncertain expectations. * * // Recommended; asserts that target doesn't have any of the given keys * expect({a: 1, b: 2}).to.not.have.any.keys('c', 'd'); * * // Not recommended; asserts that target doesn't have all of the given * // keys but may or may not have some of them * expect({a: 1, b: 2}).to.not.have.all.keys('c', 'd'); * * When asserting `.keys` without negation, `.all` is preferred because * `.all.keys` asserts exactly what's expected of the output, whereas * `.any.keys` creates uncertain expectations. * * // Recommended; asserts that target has all the given keys * expect({a: 1, b: 2}).to.have.all.keys('a', 'b'); * * // Not recommended; asserts that target has at least one of the given * // keys but may or may not have more of them * expect({a: 1, b: 2}).to.have.any.keys('a', 'b'); * * Note that `.all` is used by default when neither `.all` nor `.any` appear * earlier in the chain. However, it's often best to add `.all` anyway because * it improves readability. * * // Both assertions are identical * expect({a: 1, b: 2}).to.have.all.keys('a', 'b'); // Recommended * expect({a: 1, b: 2}).to.have.keys('a', 'b'); // Not recommended * * Add `.include` earlier in the chain to require that the target's keys be a * superset of the expected keys, rather than identical sets. * * // Target object's keys are a superset of ['a', 'b'] but not identical * expect({a: 1, b: 2, c: 3}).to.include.all.keys('a', 'b'); * expect({a: 1, b: 2, c: 3}).to.not.have.all.keys('a', 'b'); * * However, if `.any` and `.include` are combined, only the `.any` takes * effect. The `.include` is ignored in this case. * * // Both assertions are identical * expect({a: 1}).to.have.any.keys('a', 'b'); * expect({a: 1}).to.include.any.keys('a', 'b'); * * A custom error message can be given as the second argument to `expect`. * * expect({a: 1}, 'nooo why fail??').to.have.key('b'); * * The alias `.key` can be used interchangeably with `.keys`. * * @name keys * @alias key * @param {...String|Array|Object} keys * @namespace BDD * @api public */ function assertKeys (keys) { var obj = flag(this, 'object') , objType = _.type(obj) , keysType = _.type(keys) , ssfi = flag(this, 'ssfi') , isDeep = flag(this, 'deep') , str , deepStr = '' , actual , ok = true , flagMsg = flag(this, 'message'); flagMsg = flagMsg ? flagMsg + ': ' : ''; var mixedArgsMsg = flagMsg + 'when testing keys against an object or an array you must give a single Array|Object|String argument or multiple String arguments'; if (objType === 'Map' || objType === 'Set') { deepStr = isDeep ? 'deeply ' : ''; actual = []; // Map and Set '.keys' aren't supported in IE 11. Therefore, use .forEach. obj.forEach(function (val, key) { actual.push(key) }); if (keysType !== 'Array') { keys = Array.prototype.slice.call(arguments); } } else { actual = _.getOwnEnumerableProperties(obj); switch (keysType) { case 'Array': if (arguments.length > 1) { throw new AssertionError(mixedArgsMsg, undefined, ssfi); } break; case 'Object': if (arguments.length > 1) { throw new AssertionError(mixedArgsMsg, undefined, ssfi); } keys = Object.keys(keys); break; default: keys = Array.prototype.slice.call(arguments); } // Only stringify non-Symbols because Symbols would become "Symbol()" keys = keys.map(function (val) { return typeof val === 'symbol' ? val : String(val); }); } if (!keys.length) { throw new AssertionError(flagMsg + 'keys required', undefined, ssfi); } var len = keys.length , any = flag(this, 'any') , all = flag(this, 'all') , expected = keys; if (!any && !all) { all = true; } // Has any if (any) { ok = expected.some(function(expectedKey) { return actual.some(function(actualKey) { if (isDeep) { return _.eql(expectedKey, actualKey); } else { return expectedKey === actualKey; } }); }); } // Has all if (all) { ok = expected.every(function(expectedKey) { return actual.some(function(actualKey) { if (isDeep) { return _.eql(expectedKey, actualKey); } else { return expectedKey === actualKey; } }); }); if (!flag(this, 'contains')) { ok = ok && keys.length == actual.length; } } // Key string if (len > 1) { keys = keys.map(function(key) { return _.inspect(key); }); var last = keys.pop(); if (all) { str = keys.join(', ') + ', and ' + last; } if (any) { str = keys.join(', ') + ', or ' + last; } } else { str = _.inspect(keys[0]); } // Form str = (len > 1 ? 'keys ' : 'key ') + str; // Have / include str = (flag(this, 'contains') ? 'contain ' : 'have ') + str; // Assertion this.assert( ok , 'expected #{this} to ' + deepStr + str , 'expected #{this} to not ' + deepStr + str , expected.slice(0).sort(_.compareByInspect) , actual.sort(_.compareByInspect) , true ); } Assertion.addMethod('keys', assertKeys); Assertion.addMethod('key', assertKeys); /** * ### .throw([errorLike], [errMsgMatcher], [msg]) * * When no arguments are provided, `.throw` invokes the target function and * asserts that an error is thrown. * * var badFn = function () { throw new TypeError('Illegal salmon!'); }; * * expect(badFn).to.throw(); * * When one argument is provided, and it's an error constructor, `.throw` * invokes the target function and asserts that an error is thrown that's an * instance of that error constructor. * * var badFn = function () { throw new TypeError('Illegal salmon!'); }; * * expect(badFn).to.throw(TypeError); * * When one argument is provided, and it's an error instance, `.throw` invokes * the target function and asserts that an error is thrown that's strictly * (`===`) equal to that error instance. * * var err = new TypeError('Illegal salmon!'); * var badFn = function () { throw err; }; * * expect(badFn).to.throw(err); * * When one argument is provided, and it's a string, `.throw` invokes the * target function and asserts that an error is thrown with a message that * contains that string. * * var badFn = function () { throw new TypeError('Illegal salmon!'); }; * * expect(badFn).to.throw('salmon'); * * When one argument is provided, and it's a regular expression, `.throw` * invokes the target function and asserts that an error is thrown with a * message that matches that regular expression. * * var badFn = function () { throw new TypeError('Illegal salmon!'); }; * * expect(badFn).to.throw(/salmon/); * * When two arguments are provided, and the first is an error instance or * constructor, and the second is a string or regular expression, `.throw` * invokes the function and asserts that an error is thrown that fulfills both * conditions as described above. * * var err = new TypeError('Illegal salmon!'); * var badFn = function () { throw err; }; * * expect(badFn).to.throw(TypeError, 'salmon'); * expect(badFn).to.throw(TypeError, /salmon/); * expect(badFn).to.throw(err, 'salmon'); * expect(badFn).to.throw(err, /salmon/); * * Add `.not` earlier in the chain to negate `.throw`. * * var goodFn = function () {}; * * expect(goodFn).to.not.throw(); * * However, it's dangerous to negate `.throw` when providing any arguments. * The problem is that it creates uncertain expectations by asserting that the * target either doesn't throw an error, or that it throws an error but of a * different type than the given type, or that it throws an error of the given * type but with a message that doesn't include the given string. It's often * best to identify the exact output that's expected, and then write an * assertion that only accepts that exact output. * * When the target isn't expected to throw an error, it's often best to assert * exactly that. * * var goodFn = function () {}; * * expect(goodFn).to.not.throw(); // Recommended * expect(goodFn).to.not.throw(ReferenceError, 'x'); // Not recommended * * When the target is expected to throw an error, it's often best to assert * that the error is of its expected type, and has a message that includes an * expected string, rather than asserting that it doesn't have one of many * unexpected types, and doesn't have a message that includes some string. * * var badFn = function () { throw new TypeError('Illegal salmon!'); }; * * expect(badFn).to.throw(TypeError, 'salmon'); // Recommended * expect(badFn).to.not.throw(ReferenceError, 'x'); // Not recommended * * `.throw` changes the target of any assertions that follow in the chain to * be the error object that's thrown. * * var err = new TypeError('Illegal salmon!'); * err.code = 42; * var badFn = function () { throw err; }; * * expect(badFn).to.throw(TypeError).with.property('code', 42); * * `.throw` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. When not providing two arguments, always use * the second form. * * var goodFn = function () {}; * * expect(goodFn).to.throw(TypeError, 'x', 'nooo why fail??'); * expect(goodFn, 'nooo why fail??').to.throw(); * * Due to limitations in ES5, `.throw` may not always work as expected when * using a transpiler such as Babel or TypeScript. In particular, it may * produce unexpected results when subclassing the built-in `Error` object and * then passing the subclassed constructor to `.throw`. See your transpiler's * docs for details: * * - ([Babel](https://babeljs.io/docs/usage/caveats/#classes)) * - ([TypeScript](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work)) * * Beware of some common mistakes when using the `throw` assertion. One common * mistake is to accidentally invoke the function yourself instead of letting * the `throw` assertion invoke the function for you. For example, when * testing if a function named `fn` throws, provide `fn` instead of `fn()` as * the target for the assertion. * * expect(fn).to.throw(); // Good! Tests `fn` as desired * expect(fn()).to.throw(); // Bad! Tests result of `fn()`, not `fn` * * If you need to assert that your function `fn` throws when passed certain * arguments, then wrap a call to `fn` inside of another function. * * expect(function () { fn(42); }).to.throw(); // Function expression * expect(() => fn(42)).to.throw(); // ES6 arrow function * * Another common mistake is to provide an object method (or any stand-alone * function that relies on `this`) as the target of the assertion. Doing so is * problematic because the `this` context will be lost when the function is * invoked by `.throw`; there's no way for it to know what `this` is supposed * to be. There are two ways around this problem. One solution is to wrap the * method or function call inside of another function. Another solution is to * use `bind`. * * expect(function () { cat.meow(); }).to.throw(); // Function expression * expect(() => cat.meow()).to.throw(); // ES6 arrow function * expect(cat.meow.bind(cat)).to.throw(); // Bind * * Finally, it's worth mentioning that it's a best practice in JavaScript to * only throw `Error` and derivatives of `Error` such as `ReferenceError`, * `TypeError`, and user-defined objects that extend `Error`. No other type of * value will generate a stack trace when initialized. With that said, the * `throw` assertion does technically support any type of value being thrown, * not just `Error` and its derivatives. * * The aliases `.throws` and `.Throw` can be used interchangeably with * `.throw`. * * @name throw * @alias throws * @alias Throw * @param {Error|ErrorConstructor} errorLike * @param {String|RegExp} errMsgMatcher error message * @param {String} msg _optional_ * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types * @returns error for chaining (null if no error) * @namespace BDD * @api public */ function assertThrows (errorLike, errMsgMatcher, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , ssfi = flag(this, 'ssfi') , flagMsg = flag(this, 'message') , negate = flag(this, 'negate') || false; new Assertion(obj, flagMsg, ssfi, true).is.a('function'); if (errorLike instanceof RegExp || typeof errorLike === 'string') { errMsgMatcher = errorLike; errorLike = null; } var caughtErr; try { obj(); } catch (err) { caughtErr = err; } // If we have the negate flag enabled and at least one valid argument it means we do expect an error // but we want it to match a given set of criteria var everyArgIsUndefined = errorLike === undefined && errMsgMatcher === undefined; // If we've got the negate flag enabled and both args, we should only fail if both aren't compatible // See Issue #551 and PR #683@GitHub var everyArgIsDefined = Boolean(errorLike && errMsgMatcher); var errorLikeFail = false; var errMsgMatcherFail = false; // Checking if error was thrown if (everyArgIsUndefined || !everyArgIsUndefined && !negate) { // We need this to display results correctly according to their types var errorLikeString = 'an error'; if (errorLike instanceof Error) { errorLikeString = '#{exp}'; } else if (errorLike) { errorLikeString = _.checkError.getConstructorName(errorLike); } this.assert( caughtErr , 'expected #{this} to throw ' + errorLikeString , 'expected #{this} to not throw an error but #{act} was thrown' , errorLike && errorLike.toString() , (caughtErr instanceof Error ? caughtErr.toString() : (typeof caughtErr === 'string' ? caughtErr : caughtErr && _.checkError.getConstructorName(caughtErr))) ); } if (errorLike && caughtErr) { // We should compare instances only if `errorLike` is an instance of `Error` if (errorLike instanceof Error) { var isCompatibleInstance = _.checkError.compatibleInstance(caughtErr, errorLike); if (isCompatibleInstance === negate) { // These checks were created to ensure we won't fail too soon when we've got both args and a negate // See Issue #551 and PR #683@GitHub if (everyArgIsDefined && negate) { errorLikeFail = true; } else { this.assert( negate , 'expected #{this} to throw #{exp} but #{act} was thrown' , 'expected #{this} to not throw #{exp}' + (caughtErr && !negate ? ' but #{act} was thrown' : '') , errorLike.toString() , caughtErr.toString() ); } } } var isCompatibleConstructor = _.checkError.compatibleConstructor(caughtErr, errorLike); if (isCompatibleConstructor === negate) { if (everyArgIsDefined && negate) { errorLikeFail = true; } else { this.assert( negate , 'expected #{this} to throw #{exp} but #{act} was thrown' , 'expected #{this} to not throw #{exp}' + (caughtErr ? ' but #{act} was thrown' : '') , (errorLike instanceof Error ? errorLike.toString() : errorLike && _.checkError.getConstructorName(errorLike)) , (caughtErr instanceof Error ? caughtErr.toString() : caughtErr && _.checkError.getConstructorName(caughtErr)) ); } } } if (caughtErr && errMsgMatcher !== undefined && errMsgMatcher !== null) { // Here we check compatible messages var placeholder = 'including'; if (errMsgMatcher instanceof RegExp) { placeholder = 'matching' } var isCompatibleMessage = _.checkError.compatibleMessage(caughtErr, errMsgMatcher); if (isCompatibleMessage === negate) { if (everyArgIsDefined && negate) { errMsgMatcherFail = true; } else { this.assert( negate , 'expected #{this} to throw error ' + placeholder + ' #{exp} but got #{act}' , 'expected #{this} to throw error not ' + placeholder + ' #{exp}' , errMsgMatcher , _.checkError.getMessage(caughtErr) ); } } } // If both assertions failed and both should've matched we throw an error if (errorLikeFail && errMsgMatcherFail) { this.assert( negate , 'expected #{this} to throw #{exp} but #{act} was thrown' , 'expected #{this} to not throw #{exp}' + (caughtErr ? ' but #{act} was thrown' : '') , (errorLike instanceof Error ? errorLike.toString() : errorLike && _.checkError.getConstructorName(errorLike)) , (caughtErr instanceof Error ? caughtErr.toString() : caughtErr && _.checkError.getConstructorName(caughtErr)) ); } flag(this, 'object', caughtErr); }; Assertion.addMethod('throw', assertThrows); Assertion.addMethod('throws', assertThrows); Assertion.addMethod('Throw', assertThrows); /** * ### .respondTo(method[, msg]) * * When the target is a non-function object, `.respondTo` asserts that the * target has a method with the given name `method`. The method can be own or * inherited, and it can be enumerable or non-enumerable. * * function Cat () {} * Cat.prototype.meow = function () {}; * * expect(new Cat()).to.respondTo('meow'); * * When the target is a function, `.respondTo` asserts that the target's * `prototype` property has a method with the given name `method`. Again, the * method can be own or inherited, and it can be enumerable or non-enumerable. * * function Cat () {} * Cat.prototype.meow = function () {}; * * expect(Cat).to.respondTo('meow'); * * Add `.itself` earlier in the chain to force `.respondTo` to treat the * target as a non-function object, even if it's a function. Thus, it asserts * that the target has a method with the given name `method`, rather than * asserting that the target's `prototype` property has a method with the * given name `method`. * * function Cat () {} * Cat.prototype.meow = function () {}; * Cat.hiss = function () {}; * * expect(Cat).itself.to.respondTo('hiss').but.not.respondTo('meow'); * * When not adding `.itself`, it's important to check the target's type before * using `.respondTo`. See the `.a` doc for info on checking a target's type. * * function Cat () {} * Cat.prototype.meow = function () {}; * * expect(new Cat()).to.be.an('object').that.respondsTo('meow'); * * Add `.not` earlier in the chain to negate `.respondTo`. * * function Dog () {} * Dog.prototype.bark = function () {}; * * expect(new Dog()).to.not.respondTo('meow'); * * `.respondTo` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect({}).to.respondTo('meow', 'nooo why fail??'); * expect({}, 'nooo why fail??').to.respondTo('meow'); * * The alias `.respondsTo` can be used interchangeably with `.respondTo`. * * @name respondTo * @alias respondsTo * @param {String} method * @param {String} msg _optional_ * @namespace BDD * @api public */ function respondTo (method, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , itself = flag(this, 'itself') , context = ('function' === typeof obj && !itself) ? obj.prototype[method] : obj[method]; this.assert( 'function' === typeof context , 'expected #{this} to respond to ' + _.inspect(method) , 'expected #{this} to not respond to ' + _.inspect(method) ); } Assertion.addMethod('respondTo', respondTo); Assertion.addMethod('respondsTo', respondTo); /** * ### .itself * * Forces all `.respondTo` assertions that follow in the chain to behave as if * the target is a non-function object, even if it's a function. Thus, it * causes `.respondTo` to assert that the target has a method with the given * name, rather than asserting that the target's `prototype` property has a * method with the given name. * * function Cat () {} * Cat.prototype.meow = function () {}; * Cat.hiss = function () {}; * * expect(Cat).itself.to.respondTo('hiss').but.not.respondTo('meow'); * * @name itself * @namespace BDD * @api public */ Assertion.addProperty('itself', function () { flag(this, 'itself', true); }); /** * ### .satisfy(matcher[, msg]) * * Invokes the given `matcher` function with the target being passed as the * first argument, and asserts that the value returned is truthy. * * expect(1).to.satisfy(function(num) { * return num > 0; * }); * * Add `.not` earlier in the chain to negate `.satisfy`. * * expect(1).to.not.satisfy(function(num) { * return num > 2; * }); * * `.satisfy` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect(1).to.satisfy(function(num) { * return num > 2; * }, 'nooo why fail??'); * * expect(1, 'nooo why fail??').to.satisfy(function(num) { * return num > 2; * }); * * The alias `.satisfies` can be used interchangeably with `.satisfy`. * * @name satisfy * @alias satisfies * @param {Function} matcher * @param {String} msg _optional_ * @namespace BDD * @api public */ function satisfy (matcher, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object'); var result = matcher(obj); this.assert( result , 'expected #{this} to satisfy ' + _.objDisplay(matcher) , 'expected #{this} to not satisfy' + _.objDisplay(matcher) , flag(this, 'negate') ? false : true , result ); } Assertion.addMethod('satisfy', satisfy); Assertion.addMethod('satisfies', satisfy); /** * ### .closeTo(expected, delta[, msg]) * * Asserts that the target is a number that's within a given +/- `delta` range * of the given number `expected`. However, it's often best to assert that the * target is equal to its expected value. * * // Recommended * expect(1.5).to.equal(1.5); * * // Not recommended * expect(1.5).to.be.closeTo(1, 0.5); * expect(1.5).to.be.closeTo(2, 0.5); * expect(1.5).to.be.closeTo(1, 1); * * Add `.not` earlier in the chain to negate `.closeTo`. * * expect(1.5).to.equal(1.5); // Recommended * expect(1.5).to.not.be.closeTo(3, 1); // Not recommended * * `.closeTo` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect(1.5).to.be.closeTo(3, 1, 'nooo why fail??'); * expect(1.5, 'nooo why fail??').to.be.closeTo(3, 1); * * The alias `.approximately` can be used interchangeably with `.closeTo`. * * @name closeTo * @alias approximately * @param {Number} expected * @param {Number} delta * @param {String} msg _optional_ * @namespace BDD * @api public */ function closeTo(expected, delta, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(obj, flagMsg, ssfi, true).is.a('number'); if (typeof expected !== 'number' || typeof delta !== 'number') { flagMsg = flagMsg ? flagMsg + ': ' : ''; throw new AssertionError( flagMsg + 'the arguments to closeTo or approximately must be numbers', undefined, ssfi ); } this.assert( Math.abs(obj - expected) <= delta , 'expected #{this} to be close to ' + expected + ' +/- ' + delta , 'expected #{this} not to be close to ' + expected + ' +/- ' + delta ); } Assertion.addMethod('closeTo', closeTo); Assertion.addMethod('approximately', closeTo); // Note: Duplicates are ignored if testing for inclusion instead of sameness. function isSubsetOf(subset, superset, cmp, contains, ordered) { if (!contains) { if (subset.length !== superset.length) return false; superset = superset.slice(); } return subset.every(function(elem, idx) { if (ordered) return cmp ? cmp(elem, superset[idx]) : elem === superset[idx]; if (!cmp) { var matchIdx = superset.indexOf(elem); if (matchIdx === -1) return false; // Remove match from superset so not counted twice if duplicate in subset. if (!contains) superset.splice(matchIdx, 1); return true; } return superset.some(function(elem2, matchIdx) { if (!cmp(elem, elem2)) return false; // Remove match from superset so not counted twice if duplicate in subset. if (!contains) superset.splice(matchIdx, 1); return true; }); }); } /** * ### .members(set[, msg]) * * Asserts that the target array has the same members as the given array * `set`. * * expect([1, 2, 3]).to.have.members([2, 1, 3]); * expect([1, 2, 2]).to.have.members([2, 1, 2]); * * By default, members are compared using strict (`===`) equality. Add `.deep` * earlier in the chain to use deep equality instead. See the `deep-eql` * project page for info on the deep equality algorithm: * https://github.com/chaijs/deep-eql. * * // Target array deeply (but not strictly) has member `{a: 1}` * expect([{a: 1}]).to.have.deep.members([{a: 1}]); * expect([{a: 1}]).to.not.have.members([{a: 1}]); * * By default, order doesn't matter. Add `.ordered` earlier in the chain to * require that members appear in the same order. * * expect([1, 2, 3]).to.have.ordered.members([1, 2, 3]); * expect([1, 2, 3]).to.have.members([2, 1, 3]) * .but.not.ordered.members([2, 1, 3]); * * By default, both arrays must be the same size. Add `.include` earlier in * the chain to require that the target's members be a superset of the * expected members. Note that duplicates are ignored in the subset when * `.include` is added. * * // Target array is a superset of [1, 2] but not identical * expect([1, 2, 3]).to.include.members([1, 2]); * expect([1, 2, 3]).to.not.have.members([1, 2]); * * // Duplicates in the subset are ignored * expect([1, 2, 3]).to.include.members([1, 2, 2, 2]); * * `.deep`, `.ordered`, and `.include` can all be combined. However, if * `.include` and `.ordered` are combined, the ordering begins at the start of * both arrays. * * expect([{a: 1}, {b: 2}, {c: 3}]) * .to.include.deep.ordered.members([{a: 1}, {b: 2}]) * .but.not.include.deep.ordered.members([{b: 2}, {c: 3}]); * * Add `.not` earlier in the chain to negate `.members`. However, it's * dangerous to do so. The problem is that it creates uncertain expectations * by asserting that the target array doesn't have all of the same members as * the given array `set` but may or may not have some of them. It's often best * to identify the exact output that's expected, and then write an assertion * that only accepts that exact output. * * expect([1, 2]).to.not.include(3).and.not.include(4); // Recommended * expect([1, 2]).to.not.have.members([3, 4]); // Not recommended * * `.members` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. * * expect([1, 2]).to.have.members([1, 2, 3], 'nooo why fail??'); * expect([1, 2], 'nooo why fail??').to.have.members([1, 2, 3]); * * @name members * @param {Array} set * @param {String} msg _optional_ * @namespace BDD * @api public */ Assertion.addMethod('members', function (subset, msg) { if (msg) flag(this, 'message', msg); var obj = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(obj, flagMsg, ssfi, true).to.be.an('array'); new Assertion(subset, flagMsg, ssfi, true).to.be.an('array'); var contains = flag(this, 'contains'); var ordered = flag(this, 'ordered'); var subject, failMsg, failNegateMsg; if (contains) { subject = ordered ? 'an ordered superset' : 'a superset'; failMsg = 'expected #{this} to be ' + subject + ' of #{exp}'; failNegateMsg = 'expected #{this} to not be ' + subject + ' of #{exp}'; } else { subject = ordered ? 'ordered members' : 'members'; failMsg = 'expected #{this} to have the same ' + subject + ' as #{exp}'; failNegateMsg = 'expected #{this} to not have the same ' + subject + ' as #{exp}'; } var cmp = flag(this, 'deep') ? _.eql : undefined; this.assert( isSubsetOf(subset, obj, cmp, contains, ordered) , failMsg , failNegateMsg , subset , obj , true ); }); /** * ### .oneOf(list[, msg]) * * Asserts that the target is a member of the given array `list`. However, * it's often best to assert that the target is equal to its expected value. * * expect(1).to.equal(1); // Recommended * expect(1).to.be.oneOf([1, 2, 3]); // Not recommended * * Comparisons are performed using strict (`===`) equality. * * Add `.not` earlier in the chain to negate `.oneOf`. * * expect(1).to.equal(1); // Recommended * expect(1).to.not.be.oneOf([2, 3, 4]); // Not recommended * * `.oneOf` accepts an optional `msg` argument which is a custom error message * to show when the assertion fails. The message can also be given as the * second argument to `expect`. * * expect(1).to.be.oneOf([2, 3, 4], 'nooo why fail??'); * expect(1, 'nooo why fail??').to.be.oneOf([2, 3, 4]); * * @name oneOf * @param {Array<*>} list * @param {String} msg _optional_ * @namespace BDD * @api public */ function oneOf (list, msg) { if (msg) flag(this, 'message', msg); var expected = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(list, flagMsg, ssfi, true).to.be.an('array'); this.assert( list.indexOf(expected) > -1 , 'expected #{this} to be one of #{exp}' , 'expected #{this} to not be one of #{exp}' , list , expected ); } Assertion.addMethod('oneOf', oneOf); /** * ### .change(subject[, prop[, msg]]) * * When one argument is provided, `.change` asserts that the given function * `subject` returns a different value when it's invoked before the target * function compared to when it's invoked afterward. However, it's often best * to assert that `subject` is equal to its expected value. * * var dots = '' * , addDot = function () { dots += '.'; } * , getDots = function () { return dots; }; * * // Recommended * expect(getDots()).to.equal(''); * addDot(); * expect(getDots()).to.equal('.'); * * // Not recommended * expect(addDot).to.change(getDots); * * When two arguments are provided, `.change` asserts that the value of the * given object `subject`'s `prop` property is different before invoking the * target function compared to afterward. * * var myObj = {dots: ''} * , addDot = function () { myObj.dots += '.'; }; * * // Recommended * expect(myObj).to.have.property('dots', ''); * addDot(); * expect(myObj).to.have.property('dots', '.'); * * // Not recommended * expect(addDot).to.change(myObj, 'dots'); * * Strict (`===`) equality is used to compare before and after values. * * Add `.not` earlier in the chain to negate `.change`. * * var dots = '' * , noop = function () {} * , getDots = function () { return dots; }; * * expect(noop).to.not.change(getDots); * * var myObj = {dots: ''} * , noop = function () {}; * * expect(noop).to.not.change(myObj, 'dots'); * * `.change` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. When not providing two arguments, always * use the second form. * * var myObj = {dots: ''} * , addDot = function () { myObj.dots += '.'; }; * * expect(addDot).to.not.change(myObj, 'dots', 'nooo why fail??'); * * var dots = '' * , addDot = function () { dots += '.'; } * , getDots = function () { return dots; }; * * expect(addDot, 'nooo why fail??').to.not.change(getDots); * * `.change` also causes all `.by` assertions that follow in the chain to * assert how much a numeric subject was increased or decreased by. However, * it's dangerous to use `.change.by`. The problem is that it creates * uncertain expectations by asserting that the subject either increases by * the given delta, or that it decreases by the given delta. It's often best * to identify the exact output that's expected, and then write an assertion * that only accepts that exact output. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; } * , subtractTwo = function () { myObj.val -= 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended * expect(addTwo).to.change(myObj, 'val').by(2); // Not recommended * * expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended * expect(subtractTwo).to.change(myObj, 'val').by(2); // Not recommended * * The alias `.changes` can be used interchangeably with `.change`. * * @name change * @alias changes * @param {String} subject * @param {String} prop name _optional_ * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertChanges (subject, prop, msg) { if (msg) flag(this, 'message', msg); var fn = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(fn, flagMsg, ssfi, true).is.a('function'); var initial; if (!prop) { new Assertion(subject, flagMsg, ssfi, true).is.a('function'); initial = subject(); } else { new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop); initial = subject[prop]; } fn(); var final = prop === undefined || prop === null ? subject() : subject[prop]; var msgObj = prop === undefined || prop === null ? initial : '.' + prop; // This gets flagged because of the .by(delta) assertion flag(this, 'deltaMsgObj', msgObj); flag(this, 'initialDeltaValue', initial); flag(this, 'finalDeltaValue', final); flag(this, 'deltaBehavior', 'change'); flag(this, 'realDelta', final !== initial); this.assert( initial !== final , 'expected ' + msgObj + ' to change' , 'expected ' + msgObj + ' to not change' ); } Assertion.addMethod('change', assertChanges); Assertion.addMethod('changes', assertChanges); /** * ### .increase(subject[, prop[, msg]]) * * When one argument is provided, `.increase` asserts that the given function * `subject` returns a greater number when it's invoked after invoking the * target function compared to when it's invoked beforehand. `.increase` also * causes all `.by` assertions that follow in the chain to assert how much * greater of a number is returned. It's often best to assert that the return * value increased by the expected amount, rather than asserting it increased * by any amount. * * var val = 1 * , addTwo = function () { val += 2; } * , getVal = function () { return val; }; * * expect(addTwo).to.increase(getVal).by(2); // Recommended * expect(addTwo).to.increase(getVal); // Not recommended * * When two arguments are provided, `.increase` asserts that the value of the * given object `subject`'s `prop` property is greater after invoking the * target function compared to beforehand. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended * expect(addTwo).to.increase(myObj, 'val'); // Not recommended * * Add `.not` earlier in the chain to negate `.increase`. However, it's * dangerous to do so. The problem is that it creates uncertain expectations * by asserting that the subject either decreases, or that it stays the same. * It's often best to identify the exact output that's expected, and then * write an assertion that only accepts that exact output. * * When the subject is expected to decrease, it's often best to assert that it * decreased by the expected amount. * * var myObj = {val: 1} * , subtractTwo = function () { myObj.val -= 2; }; * * expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended * expect(subtractTwo).to.not.increase(myObj, 'val'); // Not recommended * * When the subject is expected to stay the same, it's often best to assert * exactly that. * * var myObj = {val: 1} * , noop = function () {}; * * expect(noop).to.not.change(myObj, 'val'); // Recommended * expect(noop).to.not.increase(myObj, 'val'); // Not recommended * * `.increase` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. When not providing two arguments, always * use the second form. * * var myObj = {val: 1} * , noop = function () {}; * * expect(noop).to.increase(myObj, 'val', 'nooo why fail??'); * * var val = 1 * , noop = function () {} * , getVal = function () { return val; }; * * expect(noop, 'nooo why fail??').to.increase(getVal); * * The alias `.increases` can be used interchangeably with `.increase`. * * @name increase * @alias increases * @param {String|Function} subject * @param {String} prop name _optional_ * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertIncreases (subject, prop, msg) { if (msg) flag(this, 'message', msg); var fn = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(fn, flagMsg, ssfi, true).is.a('function'); var initial; if (!prop) { new Assertion(subject, flagMsg, ssfi, true).is.a('function'); initial = subject(); } else { new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop); initial = subject[prop]; } // Make sure that the target is a number new Assertion(initial, flagMsg, ssfi, true).is.a('number'); fn(); var final = prop === undefined || prop === null ? subject() : subject[prop]; var msgObj = prop === undefined || prop === null ? initial : '.' + prop; flag(this, 'deltaMsgObj', msgObj); flag(this, 'initialDeltaValue', initial); flag(this, 'finalDeltaValue', final); flag(this, 'deltaBehavior', 'increase'); flag(this, 'realDelta', final - initial); this.assert( final - initial > 0 , 'expected ' + msgObj + ' to increase' , 'expected ' + msgObj + ' to not increase' ); } Assertion.addMethod('increase', assertIncreases); Assertion.addMethod('increases', assertIncreases); /** * ### .decrease(subject[, prop[, msg]]) * * When one argument is provided, `.decrease` asserts that the given function * `subject` returns a lesser number when it's invoked after invoking the * target function compared to when it's invoked beforehand. `.decrease` also * causes all `.by` assertions that follow in the chain to assert how much * lesser of a number is returned. It's often best to assert that the return * value decreased by the expected amount, rather than asserting it decreased * by any amount. * * var val = 1 * , subtractTwo = function () { val -= 2; } * , getVal = function () { return val; }; * * expect(subtractTwo).to.decrease(getVal).by(2); // Recommended * expect(subtractTwo).to.decrease(getVal); // Not recommended * * When two arguments are provided, `.decrease` asserts that the value of the * given object `subject`'s `prop` property is lesser after invoking the * target function compared to beforehand. * * var myObj = {val: 1} * , subtractTwo = function () { myObj.val -= 2; }; * * expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended * expect(subtractTwo).to.decrease(myObj, 'val'); // Not recommended * * Add `.not` earlier in the chain to negate `.decrease`. However, it's * dangerous to do so. The problem is that it creates uncertain expectations * by asserting that the subject either increases, or that it stays the same. * It's often best to identify the exact output that's expected, and then * write an assertion that only accepts that exact output. * * When the subject is expected to increase, it's often best to assert that it * increased by the expected amount. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended * expect(addTwo).to.not.decrease(myObj, 'val'); // Not recommended * * When the subject is expected to stay the same, it's often best to assert * exactly that. * * var myObj = {val: 1} * , noop = function () {}; * * expect(noop).to.not.change(myObj, 'val'); // Recommended * expect(noop).to.not.decrease(myObj, 'val'); // Not recommended * * `.decrease` accepts an optional `msg` argument which is a custom error * message to show when the assertion fails. The message can also be given as * the second argument to `expect`. When not providing two arguments, always * use the second form. * * var myObj = {val: 1} * , noop = function () {}; * * expect(noop).to.decrease(myObj, 'val', 'nooo why fail??'); * * var val = 1 * , noop = function () {} * , getVal = function () { return val; }; * * expect(noop, 'nooo why fail??').to.decrease(getVal); * * The alias `.decreases` can be used interchangeably with `.decrease`. * * @name decrease * @alias decreases * @param {String|Function} subject * @param {String} prop name _optional_ * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertDecreases (subject, prop, msg) { if (msg) flag(this, 'message', msg); var fn = flag(this, 'object') , flagMsg = flag(this, 'message') , ssfi = flag(this, 'ssfi'); new Assertion(fn, flagMsg, ssfi, true).is.a('function'); var initial; if (!prop) { new Assertion(subject, flagMsg, ssfi, true).is.a('function'); initial = subject(); } else { new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop); initial = subject[prop]; } // Make sure that the target is a number new Assertion(initial, flagMsg, ssfi, true).is.a('number'); fn(); var final = prop === undefined || prop === null ? subject() : subject[prop]; var msgObj = prop === undefined || prop === null ? initial : '.' + prop; flag(this, 'deltaMsgObj', msgObj); flag(this, 'initialDeltaValue', initial); flag(this, 'finalDeltaValue', final); flag(this, 'deltaBehavior', 'decrease'); flag(this, 'realDelta', initial - final); this.assert( final - initial < 0 , 'expected ' + msgObj + ' to decrease' , 'expected ' + msgObj + ' to not decrease' ); } Assertion.addMethod('decrease', assertDecreases); Assertion.addMethod('decreases', assertDecreases); /** * ### .by(delta[, msg]) * * When following an `.increase` assertion in the chain, `.by` asserts that * the subject of the `.increase` assertion increased by the given `delta`. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(2); * * When following a `.decrease` assertion in the chain, `.by` asserts that the * subject of the `.decrease` assertion decreased by the given `delta`. * * var myObj = {val: 1} * , subtractTwo = function () { myObj.val -= 2; }; * * expect(subtractTwo).to.decrease(myObj, 'val').by(2); * * When following a `.change` assertion in the chain, `.by` asserts that the * subject of the `.change` assertion either increased or decreased by the * given `delta`. However, it's dangerous to use `.change.by`. The problem is * that it creates uncertain expectations. It's often best to identify the * exact output that's expected, and then write an assertion that only accepts * that exact output. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; } * , subtractTwo = function () { myObj.val -= 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended * expect(addTwo).to.change(myObj, 'val').by(2); // Not recommended * * expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended * expect(subtractTwo).to.change(myObj, 'val').by(2); // Not recommended * * Add `.not` earlier in the chain to negate `.by`. However, it's often best * to assert that the subject changed by its expected delta, rather than * asserting that it didn't change by one of countless unexpected deltas. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; }; * * // Recommended * expect(addTwo).to.increase(myObj, 'val').by(2); * * // Not recommended * expect(addTwo).to.increase(myObj, 'val').but.not.by(3); * * `.by` accepts an optional `msg` argument which is a custom error message to * show when the assertion fails. The message can also be given as the second * argument to `expect`. * * var myObj = {val: 1} * , addTwo = function () { myObj.val += 2; }; * * expect(addTwo).to.increase(myObj, 'val').by(3, 'nooo why fail??'); * expect(addTwo, 'nooo why fail??').to.increase(myObj, 'val').by(3); * * @name by * @param {Number} delta * @param {String} msg _optional_ * @namespace BDD * @api public */ function assertDelta(delta, msg) { if (msg) flag(this, 'message', msg); var msgObj = flag(this, 'deltaMsgObj'); var initial = flag(this, 'initialDeltaValue'); var final = flag(this, 'finalDeltaValue'); var behavior = flag(this, 'deltaBehavior'); var realDelta = flag(this, 'realDelta'); var expression; if (behavior === 'change') { expression = Math.abs(final - initial) === Math.abs(delta); } else { expression = realDelta === Math.abs(delta); } this.assert( expression , 'expected ' + msgObj + ' to ' + behavior + ' by ' + delta , 'expected ' + msgObj + ' to not ' + behavior + ' by ' + delta ); } Assertion.addMethod('by', assertDelta); /** * ### .extensible * * Asserts that the target is extensible, which means that new properties can * be added to it. Primitives are never extensible. * * expect({a: 1}).to.be.extensible; * * Add `.not` earlier in the chain to negate `.extensible`. * * var nonExtensibleObject = Object.preventExtensions({}) * , sealedObject = Object.seal({}) * , frozenObject = Object.freeze({}); * * expect(nonExtensibleObject).to.not.be.extensible; * expect(sealedObject).to.not.be.extensible; * expect(frozenObject).to.not.be.extensible; * expect(1).to.not.be.extensible; * * A custom error message can be given as the second argument to `expect`. * * expect(1, 'nooo why fail??').to.be.extensible; * * @name extensible * @namespace BDD * @api public */ Assertion.addProperty('extensible', function() { var obj = flag(this, 'object'); // In ES5, if the argument to this method is a primitive, then it will cause a TypeError. // In ES6, a non-object argument will be treated as if it was a non-extensible ordinary object, simply return false. // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible // The following provides ES6 behavior for ES5 environments. var isExtensible = obj === Object(obj) && Object.isExtensible(obj); this.assert( isExtensible , 'expected #{this} to be extensible' , 'expected #{this} to not be extensible' ); }); /** * ### .sealed * * Asserts that the target is sealed, which means that new properties can't be * added to it, and its existing properties can't be reconfigured or deleted. * However, it's possible that its existing properties can still be reassigned * to different values. Primitives are always sealed. * * var sealedObject = Object.seal({}); * var frozenObject = Object.freeze({}); * * expect(sealedObject).to.be.sealed; * expect(frozenObject).to.be.sealed; * expect(1).to.be.sealed; * * Add `.not` earlier in the chain to negate `.sealed`. * * expect({a: 1}).to.not.be.sealed; * * A custom error message can be given as the second argument to `expect`. * * expect({a: 1}, 'nooo why fail??').to.be.sealed; * * @name sealed * @namespace BDD * @api public */ Assertion.addProperty('sealed', function() { var obj = flag(this, 'object'); // In ES5, if the argument to this method is a primitive, then it will cause a TypeError. // In ES6, a non-object argument will be treated as if it was a sealed ordinary object, simply return true. // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed // The following provides ES6 behavior for ES5 environments. var isSealed = obj === Object(obj) ? Object.isSealed(obj) : true; this.assert( isSealed , 'expected #{this} to be sealed' , 'expected #{this} to not be sealed' ); }); /** * ### .frozen * * Asserts that the target is frozen, which means that new properties can't be * added to it, and its existing properties can't be reassigned to different * values, reconfigured, or deleted. Primitives are always frozen. * * var frozenObject = Object.freeze({}); * * expect(frozenObject).to.be.frozen; * expect(1).to.be.frozen; * * Add `.not` earlier in the chain to negate `.frozen`. * * expect({a: 1}).to.not.be.frozen; * * A custom error message can be given as the second argument to `expect`. * * expect({a: 1}, 'nooo why fail??').to.be.frozen; * * @name frozen * @namespace BDD * @api public */ Assertion.addProperty('frozen', function() { var obj = flag(this, 'object'); // In ES5, if the argument to this method is a primitive, then it will cause a TypeError. // In ES6, a non-object argument will be treated as if it was a frozen ordinary object, simply return true. // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen // The following provides ES6 behavior for ES5 environments. var isFrozen = obj === Object(obj) ? Object.isFrozen(obj) : true; this.assert( isFrozen , 'expected #{this} to be frozen' , 'expected #{this} to not be frozen' ); }); /** * ### .finite * * Asserts that the target is a number, and isn't `NaN` or positive/negative * `Infinity`. * * expect(1).to.be.finite; * * Add `.not` earlier in the chain to negate `.finite`. However, it's * dangerous to do so. The problem is that it creates uncertain expectations * by asserting that the subject either isn't a number, or that it's `NaN`, or * that it's positive `Infinity`, or that it's negative `Infinity`. It's often * best to identify the exact output that's expected, and then write an * assertion that only accepts that exact output. * * When the target isn't expected to be a number, it's often best to assert * that it's the expected type, rather than asserting that it isn't one of * many unexpected types. * * expect('foo').to.be.a('string'); // Recommended * expect('foo').to.not.be.finite; // Not recommended * * When the target is expected to be `NaN`, it's often best to assert exactly * that. * * expect(NaN).to.be.NaN; // Recommended * expect(NaN).to.not.be.finite; // Not recommended * * When the target is expected to be positive infinity, it's often best to * assert exactly that. * * expect(Infinity).to.equal(Infinity); // Recommended * expect(Infinity).to.not.be.finite; // Not recommended * * When the target is expected to be negative infinity, it's often best to * assert exactly that. * * expect(-Infinity).to.equal(-Infinity); // Recommended * expect(-Infinity).to.not.be.finite; // Not recommended * * A custom error message can be given as the second argument to `expect`. * * expect('foo', 'nooo why fail??').to.be.finite; * * @name finite * @namespace BDD * @api public */ Assertion.addProperty('finite', function(msg) { var obj = flag(this, 'object'); this.assert( typeof obj === 'number' && isFinite(obj) , 'expected #{this} to be a finite number' , 'expected #{this} to not be a finite number' ); }); };