Vanilla mocks on Jasmine

In

Set up

  • Mock the method getFlag on myApp. 
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    spyOn(myApp, "getFlag");

Mocks

Return values

  • Simple

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    spyOn(myApp, "getFlag").and.returnValue(true);

  • Fake Functions

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    spyOn(myApp, "useFlagForSomething").and.callFake(function() {
        return "I'm replacing the real function with this";
    });

Verify code was called

  • Verify called

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    spyOn(myApp, "getFlag").and.callThrough();

  • Verify not called

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    expect(myApp.reallyImportantProcess).not.toHaveBeenCalled();

  • Assert on function call

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    expect(myApp.reallyImportantProcess).toHaveBeenCalledWith(123, "abc");

Async tests

  • Code example

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    var flag = false;

    function testAsync(done) {
        // Wait two seconds, then set the flag to true
        setTimeout(function () {
            flag = true;
        }, 2000);
    }

  • Specs

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    describe("Testing async calls with beforeEach and passing callback", function () {
        beforeEach(function (done) {
            // Make an async call, passing the special done callback        
            testAsync(done);
        });

        it("Should be true if the async call has completed", function () {
            expect(flag).toEqual(true);
        });
    });

Async-await

  • Code example

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    function returnTrueAsync() {
        return new Promise(resolve => {
            setTimeout(() => {
            resolve(true);
            }, 1000);
        });
    }

  • Specs

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    describe("Testing async functions", () => {  
        it("Should work with async/await", async () => {
            // Arrange
            let flag = false;

            // Act
            flag = await returnTrueAsync();

            // Assert
            expect(flag).toBeTruthy();
        });
    });