Jasmine - why JS tests don't smell fishy

Jasmine - why JS tests don't smell fishy

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  1 JASMINEWhy JavaScript testsdon’t smell fishy?
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  WHAT I WILLTALK ABOUT: 2 • What is Unit Testing • Solution: Jasmine - whole syntax with examples • WebStorm goodies • Benefits of Units Tests • Why people don’t test JavaScript? • Test Driven Development, Behavior Driven Development
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  WHY PEOPLE DON’TTEST JAVASCRIPT ? • project not big enough • project too complex • asynchronous XHR requests • DOM manipulation • too many browsers, platforms, devices 3
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  UNIT TESTING isa program (test case or test specification) that isolates and tests small and specific functional unit of code. Test one small functionality per suite. Not too many things at one time. Remember! It impossible to write test for every case - try to cover every reasonable case, remember about corner cases 4 GOOD PRACTICES
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  BENEFITS OF USINGJAVASCRIPT TESTS 5 • QA phase is cheaper - you will uncover bugs earlier • Creates great documentation • As a developer you will write better code • Shows that JS should work as was designed • Quick and easy to run - try to do it with manual testing • Runs the same every time
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  TDD & BDD BehaviorDriven Development: agile software development technique testing from business value perspective, why some code is necessary and what its goal is 6 Test Driven Development: write tests against specification, watch your test fail, write some code, test, refactor, test-fix-implement
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  TDD vs BDD Example:10 sorting methods TDD: one test per one method - focused on „how” each method works BDD: one test per all methods - focused on the goal give an array, sort, result 7
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  JASMINE MATCHERS -EQUALITY expect(true).toEqual(true); expect({}).toEqual({}); 8 toEqual
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  JASMINE MATCHERS -IDENTITY var spot = { species: "Border Collie" }; var cosmo = { species: "Border Collie" }; // success; equivalent expect(spot).toEqual(cosmo); // failure; not the same object expect(spot).toBe(cosmo); // success; the same value expect(2).toBe(2); toBe checks if two things are the same value and type, using === Primitive Types vs Reference Types primitive will be give you true, reference will give you false 9
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  JASMINE MATCHERS -BOOLEAN expect(true).toBeTruthy(); expect(12).toBeTruthy(); expect({}).toBeTruthy(); expect(false).toBeFalsy(); expect(null).toBeFalsy(); expect("").toBeFalsy(); //false, 0, “”, undefinded, null, NaN toBeTruthy toBeFalsy10
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  JASMINE MATCHERS -NEGATION expect(this).not.toEqual(that); expect({}).not.toBe([]); not11
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  JASMINE MATCHERS -CONTAINS expect([1, 2, 3, 4]).toContain(3); expect(["Jasmine", "Qunit", "Mocha", "Casper"]).toContain("Jasmine"); expect("Rychu Peja to pener").toContain("pener"); var dog = { name: "Reksio" }; expect([ { name: "Dżeki" }, { name: "Max" }, { name: "Reksio" } ]).toContain(dog); toContain12
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  JASMINE MATCHERS -DEFINED OR UNDEFINED var somethingUndefined; expect("Hello!").toBeDefined(); // success expect(null).toBeDefined(); // success expect(somethingUndefined).toBeDefined(); // failure var somethingElseUndefined; expect(somethingElseUndefined).toBeUndefined(); // success expect(2013).toBeUndefined(); // failure expect(null).toBeUndefined(); // failure toBeDefined toBeUndefined13
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  JASMINE MATCHERS -NULLNESS expect(null).toBeNull(); // success expect(false).toBeNull(); // failure expect(somethingUndefined).toBeNull(); // failure //null is where the thing is known to exist, //but it's not known what the value is. toBeNull14
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  JASMINE MATCHERS -IS NaN expect(5).not.toBeNaN(); // success expect(0 / 0).toBeNaN(); // success expect(parseInt("hello")).toBeNaN(); // success /* This is different from JavaScript’s built-in isNaN function. The built-in isNaN will return true for many nonnumber types, such as nonnumeric strings, objects, and arrays. Jasmine’s will be positive only if it’s the NaN value. */ toBeNaN15
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  JASMINE MATCHERS -COMPARATORS expect(8).toBeGreaterThan(5); expect(5).toBeLessThan(12); expect("a").toBeLessThan("z"); // it works for strings toBeGreaterThan toBeLessThan16
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  JASMINE MATCHERS -NEARNESS expect(12.34).toBeCloseTo(12.3, 1); // success toBeCloseTo17
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  JASMINE MATCHERS -REGULAR EXPRESSIONS expect("some words").toMatch(/some/); // success toMatch18
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  JASMINE MATCHERS -ERROR THROWING var errorThrower = function () { throw new Error(); } expect(errorThrower).toThrow(); // success toThrow19
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  JASMINE - BEFOREAND AFTER TESTS var player, wallet; // remember about scope beforeEach( function () { player = new Player; }); afterEach( function () { wallet.empty(); // empty after each test }); beforeEach afterEach20
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  JASMINE MATCHERS -CUSTOM MATCHERS beforeEach( function () { this.addMatchers({ toBeLarge: function () { this.message = function () { return "Expected " + this.actual + " to be large"; }; return this.actual > 100; } }); }); expect(5).toBeLarge(); // failure expect(101).toBeLarge(); // success custom matchers21
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  JASMINE - NESTEDSUITS describe("Expected ", function () { describe("something ", function () { it("should do something", function () { expect(2).toBe(2); }); }); }); 22 describe describe
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  JASMINE - SKIPTHE TEST describe("Expected ", function () { xdescribe("something ", function () { xit("should do something", function () { expect(2).toBe(2); }); return; it("should do something else", function () { expect(3).toBe(3); }); }); }); 23 xit xdescribe return
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  JASMINE - SPIES varDictionary = function() {}, Person = function() {}; Dictionary.prototype.hello = function () { return "hello"; }; Dictionary.prototype.world = function () { return "world"; }; Person.prototype.sayHelloWorld = function(dict) { return dict.hello() + " " + dict.world(); }; var dictionary = new Dictionary, person = new Person; person.sayHelloWorld(dictionary); // returns "hello world" describe("Person", function() { it('uses the dict to say "hello world"', function() { var dictionary = new Dictionary, person = new Person; // replace each function with a spy spyOn(dictionary, "hello"); spyOn(dictionary, "world"); person.sayHelloWorld(dictionary); // not possible without first spies expect(dictionary.hello).toHaveBeenCalled(); expect(dictionary.world).toHaveBeenCalled(); }); }); toHaveBeenCalled Often you test more than variable checks. Spy can pretend that he is a function or an object. 24
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  JASMINE - SPIEScan call through the function describe("Person", function() { it('uses the dictionary to say "hello world"', function () { var dictionary = new Dictionary, person = new Person; spyOn(person, "sayHelloWorld"); // replace hello world function with a spy person.sayHelloWorld(dictionary); expect(person.sayHelloWorld).toHaveBeenCalledWith(dictionary); }); }); toHaveBeenCalledWith25
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  JASMINE - SPIEScan return specific value it("spy can return specific value", function () { var dictionary = new Dictionary, person = new Person, result; spyOn(dictionary, "hello").andReturn("Witaj"); result = person.sayHelloWorld(dictionary); expect(result).toEqual("Witaj world"); }); andReturn26
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  JASMINE - SPIEScan count its calls callCount it("can count calls of spy", function () { var dictionary = new Dictionary, spy; spy = spyOn(dictionary, "hello"); dictionary.hello(); expect(spy.callCount).toEqual(1); }); 27
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  JASMINE - SPIEScan get recent arguments mostRecentCall.args it("can give you last arguments", function () { var dictionary = new Dictionary, person = new Person, spy; spy = spyOn(person, "sayHelloWorld"); person.sayHelloWorld("No siemano"); // remember arguments will be in array expect(spy.mostRecentCall.args).toEqual(["No siemano"]); }); 28
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  JASMINE - SPIEScan get arguments of specific call argsForCall[index] it("can give you last arguments", function () { var dictionary = new Dictionary, person = new Person, spy; spy = spyOn(person, "sayHelloWorld"); person.sayHelloWorld("No siemano"); person.sayHelloWorld("Hejka"); // remember arguments will be in array and argForCall is also array expect(spy.argsForCall[1]).toEqual(["Hejka"]); }); 29
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  JASMINE - SPIEScan call fake functions it("can call a fake function", function() { var fakeHello = function() { console.log("I’m a fake function"); return "hello"; }; var dictionary = new Dictionary(); spyOn(dictionary, "hello").andCallFake(fakeHello); dictionary.hello(); // does an log }); andCallFake30
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  JASMINE - SPIEScan be created on its own it("can have a spy function", function() { var person = new Person(); person.getName = jasmine.createSpy("Name spy"); person.getName(); expect(person.getName).toHaveBeenCalled(); }); jasmine.createSpy31
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  32 JASMINE - SPIEScan chain actions person.getSecretAgentName = jasmine.createSpy("Name spy").andReturn("James Bond"); chaning
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  JASMINE - SPIEScan be an object it("spy can be an object", function() { var player = jasmine.createSpyObj("player", ["hustle", "rap"]); player.hustle(); // magic to test }); jasmine.createSpyObj33
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  JASMINE - asynchronous- RUNS it("runnin’", function() { runs(function() { it("should do something", function () { expect(2).toBe(2); }); }); }); runs34
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  JASMINE - asynchronous- WAITS it('should be a test', function () { runs(function () { this.foo = 0; var that = this; setTimeout(function () { that.foo++; }, 250); }); runs(function () { expect(this.foo).toEqual(0); }); waits(1000); runs(function () { expect(this.foo).toEqual(1); }); }); waits35
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  36 JASMINE - asynchronous- WAITS FOR describe('asynchronous wait for', function() { it('should wait for something', function () { var spreadsheet = new Spreadsheet(); waitsFor(function() { return true; // here you can call your function which should be true }, "Something went wrong", 3000); runs(function () { expect(2).toEqual(2); }); }); }); waitsFor(function, opt message, opt timeout)
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  JASMINE - jQuerymatchers toBe(jQuerySelector) toBeChecked() toBeEmpty() toBeHidden() toHaveCss(css) toBeSelected() toBeVisible() toContain(jQuerySelector) toExist() toHaveAttr(attributeName, attributeValue) toHaveProp(propertyName, propertyValue) toHaveBeenTriggeredOn(selector) toHaveBeenTriggered() toHaveBeenTriggeredOnAndWith(selector, extraParameters) toHaveBeenPreventedOn(selector) toHaveBeenPrevented() toHaveClass(className) toHaveData(key, value) toHaveHtml(string) toContainHtml(string) toContainText(string) toHaveId(id) toHaveText(string) toHaveValue(value) toHaveLength(value) toBeDisabled() toBeFocused() toHandle(eventName) toHandleWith(eventName, eventHandler) 37
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  JASMINE - HTML& JSON fixtures //myfixture.html <div id="my-fixture">some complex content here</div> //some fixture adding loadFixtures('myfixture.html'); $('#my-fixture').myTestedPlugin(); expect($('#my-fixture')).toBe('div'); 38
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  JASMINE for AJAX 39 Sinon JasmineAJAX
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  Github Present forWebStorm users 40 https://github.com/thisisui/jetbrains-jasmine-test-startup
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  41 THANKS FOR YOURTIME QUESTIONS?