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How to use mustImplement method in Jest

Best JavaScript code snippet using jest

message_channel.js

Source:message_channel.js

...29        @param {String} eventName the name of the event30        @param {Function} callback the callback to call when the event occurs31        @param {any?} binding an optional value of `this` inside of the callback32      */33      on: mustImplement('OasisPort', 'on'),34      /**35        Allows you to register an event handler that is called for all events36        that are sent to the port.37      */38      all: mustImplement('OasisPort', 'all'),39      /**40        This allows you to unregister an event handler for an event name41        and callback. You should not pass in the optional binding.42        @param {String} eventName the name of the event43        @param {Function} callback a reference to the callback that was44          passed into `.on`.45      */46      off: mustImplement('OasisPort', 'off'),47      /**48        This method sends an event to the other side of the connection.49        @param {String} eventName the name of the event50        @param {Structured?} data optional data to pass along with the event51      */52      send: mustImplement('OasisPort', 'send'),53      /**54        Adapters should implement this to start receiving messages from the55        other side of the connection.56        It is up to the adapter to make sure that no messages are dropped if57        they are sent before `start` is called.58      */59      start: mustImplement('OasisPort', 'start'),60      /**61        Adapters should implement this to stop receiving messages from the62        other side of the connection.63      */64      close: mustImplement('OasisPort', 'close'),65      /**66        This method sends a request to the other side of the connection.67        @param {String} requestName the name of the request68        @return {Promise} a promise that will be resolved with the value69          provided by the other side of the connection, or rejected if the other70          side indicates retrieving the value resulted in an error. The fulfillment71          value must be structured data.72      */73      request: function(eventName) {74        var oasis = this.oasis;75        var port = this;76        var args = [].slice.call(arguments, 1);77        return new RSVP.Promise(function (resolve, reject) {78          var requestId = getRequestId(oasis);79          var clearObservers = function () {80            port.off('@response:' + eventName, observer);81            port.off('@errorResponse:' + eventName, errorObserver);82          };83          var observer = function(event) {84            if (event.requestId === requestId) {85              clearObservers();86              resolve(event.data);87            }88          };89          var errorObserver = function (event) {90            if (event.requestId === requestId) {91              clearObservers();92              reject(event.data);93            }94          };95          port.on('@response:' + eventName, observer, port);96          port.on('@errorResponse:' + eventName, errorObserver, port);97          port.send('@request:' + eventName, { requestId: requestId, args: args });98        });99      },100      /**101        This method registers a callback to be called when a request is made102        by the other side of the connection.103        The callback will be called with any arguments passed in the request.  It104        may either return a value directly, or return a promise if the value must be105        retrieved asynchronously.106        Examples:107          // This completes the request immediately.108          service.onRequest('name', function () {109            return 'David';110          });111          // This completely the request asynchronously.112          service.onRequest('name', function () {113            return new Oasis.RSVP.Promise(function (resolve, reject) {114              setTimeout( function() {115                resolve('David');116              }, 200);117            });118          });119        @param {String} requestName the name of the request120        @param {Function} callback the callback to be called when a request121          is made.122        @param {any?} binding the value of `this` in the callback123      */124      onRequest: function(eventName, callback, binding) {125        var self = this;126        this.on('@request:' + eventName, function(data) {127          var requestId = data.requestId,128              args = data.args,129              getResponse = new RSVP.Promise(function (resolve, reject) {130                var value = callback.apply(binding, data.args);131                if (undefined !== value) {132                  resolve(value);133                } else {134                  reject("@request:" + eventName + " [" + data.requestId + "] did not return a value.  If you want to return a literal `undefined` return `RSVP.resolve(undefined)`");135                }136              });137          getResponse.then(function (value) {138            self.send('@response:' + eventName, {139              requestId: requestId,140              data: value141            });142          }, function (error) {143            var value = error;144            if (error instanceof Error) {145              value = {146                message: error.message,147                stack: error.stack148              };149            }150            self.send('@errorResponse:' + eventName, {151              requestId: requestId,152              data: value153            });154          });155        });156      }157    };158    function OasisMessageChannel(oasis) {}159    OasisMessageChannel.prototype = {160      start: mustImplement('OasisMessageChannel', 'start')161    };162    var PostMessageMessageChannel = extend(OasisMessageChannel, {163      initialize: function(oasis) {164        this.channel = new MessageChannel();165        this.port1 = new PostMessagePort(oasis, this.channel.port1);166        this.port2 = new PostMessagePort(oasis, this.channel.port2);167      },168      start: function() {169        this.port1.start();170        this.port2.start();171      },172      destroy: function() {173        this.port1.close();174        this.port2.close();...

base_adapter.js

Source:base_adapter.js

...14    function BaseAdapter() {15      this._unsupportedCapabilities = [];16    }17    BaseAdapter.prototype = {18      initializeSandbox: mustImplement('BaseAdapter', 'initializeSandbox'),19      name: mustImplement('BaseAdapter', 'name'),20      unsupportedCapabilities: function () {21        return this._unsupportedCapabilities;22      },23      addUnsupportedCapability: function (capability) {24        this._unsupportedCapabilities.push(capability);25      },26      filterCapabilities: function(capabilities) {27        var unsupported = this._unsupportedCapabilities;28        return a_filter.call(capabilities, function (capability) {29          var index = a_indexOf.call(unsupported, capability);30          return index === -1;31        });32      },33      createChannel: function(oasis) {...

snapshot_resolver.js

Source:snapshot_resolver.js

...38  snapshotResolverPath: Path,39): SnapshotResolver {40  const custom = (require(snapshotResolverPath): SnapshotResolver);41  if (typeof custom.resolveSnapshotPath !== 'function') {42    throw new TypeError(mustImplement('resolveSnapshotPath'));43  }44  if (typeof custom.resolveTestPath !== 'function') {45    throw new TypeError(mustImplement('resolveTestPath'));46  }47  const customResolver = {48    resolveSnapshotPath: testPath =>49      custom.resolveSnapshotPath(testPath, DOT_EXTENSION),50    resolveTestPath: snapshotPath =>51      custom.resolveTestPath(snapshotPath, DOT_EXTENSION),52  };53  verifyConsistentTransformations(customResolver);54  return customResolver;55}56function mustImplement(functionName: string) {57  return (58    chalk.bold(59      `Custom snapshot resolver must implement a \`${functionName}\` function.`,60    ) +61    '\nDocumentation: https://facebook.github.io/jest/docs/en/configuration.html#snapshotResolver'62  );63}64function verifyConsistentTransformations(custom: SnapshotResolver) {65  const fakeTestPath = path.posix.join(66    'some-path',67    '__tests__',68    'snapshot_resolver.test.js',69  );70  const transformedPath = custom.resolveTestPath(...

bin.js

Source:bin.js

...3export default function Bin(content, width) {4  this.width = width || 0;5  this.content = content;6}7function mustImplement(name) {8  return function() {9    throw new TypeError("MustImplement: " + name );10  };11}12// abstract13Bin.prototype.objectAt = function (collection, index) {14  return collection[index];15};16// abstract: return coordinates of element at index.17//18// @param index: index of the element in content19// @param width: viewport width.20// @returns {x, y} coordinates of element at index.21//22// May reset cached viewport width.23Bin.prototype.position = mustImplement('position');24// abstract: reset internal state to be anchored at index.25// @param index: index of the element in content26Bin.prototype.flush = mustImplement('flush');27// abstract: return total content height given viewport width.28// @param width: viewport width29//30// May reset cached viewport width.31Bin.prototype.height = mustImplement('height');32// abstract: true if layout places more than one object on a line.33Bin.prototype.isGrid = mustImplement('isGrid');34export function rangeError(length, index) {35  throw new RangeError("Parameter must be within: [" + 0 + " and " + length + ") but was: " + index);36}37// abstract: returns number of elements in content.38Bin.prototype.length = function () {39  return this.content.length;40};41// maximum offset of content wrt to viewport42// The amount by which content (after being layed out) is taller than43// the viewport.44Bin.prototype.maxContentOffset = function Bin_maxContentOffset(width, height) {45  var contentHeight = this.height(width);46  var maxOffset = Math.max(contentHeight - height, 0);47  return maxOffset;48}49// abstract: returns index of first visible item.50// @param topOffset: scroll position51// @param width: width of viewport52// @param height: height of viewport53//54Bin.prototype.visibleStartingIndex = mustImplement('visibleStartingIndex');55// abstract: returns number of items visible in viewport.56// @param topOffset: scroll position57// @param width: width of viewport58// @param height: height of viewport59Bin.prototype.numberVisibleWithin = mustImplement('numberVisibleWithin');60Bin.prototype.heightAtIndex = function (index) {61  return this.content[index].height;62};63Bin.prototype.widthAtIndex = function (index) {64  return this.content[index].width;...

util.js

Source:util.js

...11        throw new Error(string);12      }13    }14    function noop() { }15    function mustImplement(className, name) {16      return function() {17        throw new Error("Subclasses of " + className + " must implement " + name);18      };19    }20    function extend(parent, object) {21      function OasisObject() {22        parent.apply(this, arguments);23        if (this.initialize) {24          this.initialize.apply(this, arguments);25        }26      }27      OasisObject.prototype = o_create(parent.prototype);28      for (var prop in object) {29        if (!object.hasOwnProperty(prop)) { continue; }...

outcome.mjs

Source:outcome.mjs

2  static of(result) {3    return new Success(result);4  }5  map(f) {6    mustImplement();7  }8  forEach(f) {9    mustImplement();10  }11  chain(f) {12    mustImplement();13  }14}15export class Success extends Outcome {16  constructor(result) {17    super();18    this.success = true;19    this.result = result;20  }21  // f: A => B22  // ret: Outcome<B>23  map(f) {24    return new Success(f(this.result));25  }26  // f: A => void27  // ret: Outcome<A>28  forEach(f) {29    f(this.result);30    return this;31  }32  // f: A => Outcome<B>33  // ret: Outcome<B>34  chain(f) {35    return f(this.result);36  }37}38export class Failure extends Outcome {39  constructor(error, subErrors) {40    super();41    this.success = false;42    this.result = error;43    this.subErrors = subErrors;44  }45  toString() {46    return `Failure { result: ${this.result}, subErrors: ${this.subErrors} }`;47  }48  // f: A => B49  // ret: Outcome<B>50  map(f) {51    return this;52  }53  // f: A => void54  // ret: Outcome<A>55  forEach(f) {56    return this;57  }58  // f: A => Outcome<B>59  // ret: Outcome<B>60  chain(f) {61    return this;62  }63}64function mustImplement() {65  throw new Error('Must implement');...

interface.js

Source:interface.js

...3 *  4 *  The interface all dialogs must implement.5**/6Dialog.Interface = (function() {7	function mustImplement(failureMessage) {8		return function() {9			Dialog.error(message);10			throw message;11		};12	}13	14	return {15        /**16         *  Dialog.Interface.getFrame() -> Element17         *  18         *  Should be implemented to return the dialog's outermost element.19        **/20		getFrame: mustImplement('getFrame() must be implemented to return the outermost dialog frame.'),21        /**22         *  Dialog.Interface.close() -> undefined23         *  24         *  Should be implemented to close and dispose of the dialog.25        **/26		close: mustImplement('close() must be implemented to close the dialog.'),27        /**28         *  Dialog.Interface.isModal() -> Boolean29         *  30         *  Should return true if the dialog is intended to be modal, false otherwise (the default).31        **/32		isModal: function() {33			return false;34		},35		36		callback: function(which) {37			if (this.options[which] && Object.isFunction(this.options[which])) {38				return this.options[which]();39			}40		}...

adapter.js

Source:adapter.js

1function mustImplement(message) {2  var fn = function() {3    var className = this.constructor.toString();4    throw new Error(message.replace('{{className}}', className));5  };6  fn.isUnimplemented = true;7  return fn;8}9Ember.Adapter = Ember.Object.extend({10  find: mustImplement('{{className}} must implement find'),11  findQuery: mustImplement('{{className}} must implement findQuery'),12  findMany: mustImplement('{{className}} must implement findMany'),13  findAll: mustImplement('{{className}} must implement findAll'),14  createRecord: mustImplement('{{className}} must implement createRecord'),15  saveRecord: mustImplement('{{className}} must implement saveRecord'),16  deleteRecord: mustImplement('{{className}} must implement deleteRecord'),17  load: function(record, id, data) {18    record.load(id, data);19  }...

Jest Testing Tutorial

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Chapters

What is Jest Framework
Advantages of Jest - Jest has 3,898,000 GitHub repositories, as mentioned on its official website. Learn what makes Jest special and why Jest has gained popularity among the testing and developer community.
Jest Installation - All the prerequisites and set up steps needed to help you start Jest automation testing.
Using Jest with NodeJS Project - Learn how to leverage Jest framework to automate testing using a NodeJS Project.
Writing First Test for Jest Framework - Get started with code-based tutorial to help you write and execute your first Jest framework testing script.
Jest Vocabulary - Learn the industry renowned and official jargons of the Jest framework by digging deep into the Jest vocabulary.
Unit Testing with Jest - Step-by-step tutorial to help you execute unit testing with Jest framework.
Jest Basics - Learn about the most pivotal and basic features which makes Jest special.
Jest Parameterized Tests - Avoid code duplication and fasten automation testing with Jest using parameterized tests. Parameterization allows you to trigger the same test scenario over different test configurations by incorporating parameters.
Jest Matchers - Enforce assertions better with the help of matchers. Matchers help you compare the actual output with the expected one. Here is an example to see if the object is acquired from the correct class or not. -

|it('check_object_of_Car', () => { expect(newCar()).toBeInstanceOf(Car); });| | :- |

Jest Hooks: Setup and Teardown - Learn how to set up conditions which needs to be followed by the test execution and incorporate a tear down function to free resources after the execution is complete.
Jest Code Coverage - Unsure there is no code left unchecked in your application. Jest gives a specific flag called --coverage to help you generate code coverage.
HTML Report Generation - Learn how to create a comprehensive HTML report based on your Jest test execution.
Testing React app using Jest Framework - Learn how to test your react web-application with Jest framework in this detailed Jest tutorial.
Test using LambdaTest cloud Selenium Grid - Run your Jest testing script over LambdaTest cloud-based platform and leverage parallel testing to help trim down your test execution time.
Snapshot Testing for React Front Ends - Capture screenshots of your react based web-application and compare them automatically for visual anomalies with the help of Jest tutorial.
Bonus: Import ES modules with Jest - ES modules are also known as ECMAScript modules. Learn how to best use them by importing in your Jest testing scripts.
Jest vs Mocha vs Jasmine - Learn the key differences between the most popular JavaScript-based testing frameworks i.e. Jest, Mocha, and Jasmine.
Jest FAQs(Frequently Asked Questions) - Explore the most commonly asked questions around Jest framework, with their answers.