Lezione 01

Introduzione al testing in javascript

Alca Società Cooperativa http://alcacoop.it
Released under CC BY-NC-SA 3.0

Jasmine

Behavior-driven development SYNTAX

describe: identifica la suite
it: identifica la specifica
expect: identifica l'assertion

describe("A suite", function() {
  it("contains spec with an expectation", function() {
    expect(true).toBe(true);
  });
});

Jasmine - Matchers

Ogni matcher effettua un confronto booleano tra il valore attuale e quello atteso
Segnala a Jasmine se l'assertion è vera o falsa
Jasmine quindi farà fallire o passare la specifica

expect(foo).toEqual(bar);
expect(true).not.toEqual(false);

Un matcher può valutare un'assertion negativa incatenando un not alla chiamata ad expect prima di chiamare il matcher

Included matchers

toBe

describe("the toBe Matcher", function() {
  it("should compare both types and values", function() {
    var actual = "123";
    var expected = "123";
    expect(actual).toBe(expected);
  });
});

Included matchers

toEqual

describe("the toEqual Matcher", function() {
  it("should be able to compare arrays", function() {
    var actual = [1, 2, 3];
    var expected = [1, 2, 3];
    expect(actual).toEqual(expected);
  });
});

Included matchers

toBeDefined and toBeUndefined

describe("the toBeDefined and toBeUndefined Matchers", function() {
  it("should be able to check defined and  undefined objects", function() {
    var object1 = {prop1: "value1"};
    var object2;
    expect(object1).toBeDefined();
    expect(object2).toBeUndefined();
    expect(object2).not.toBeDefined();
  });
});

Included matchers

toBeNull

describe("the toBeNull Matcher", function() {
  it("should be able to check if an object value is null",
    function() {
      var object = null;
      expect(object).toBeNull();
  });
});

Included matchers

toContain

describe("the toContain Matcher", function() {
  it("should check if a String contains a substring", function() {
    expect("Hello World from Cairo").toContain("Cairo");
  });
  it("should check if an Array contains a specific item", function() {
    expect(["TV", "Watch", "Table"]).toContain("Watch");
  });
});

Included matchers

toBeLessThan and toBeGreatherThan

describe("the toBeLessThan Matcher", function() {
  it("should be able to perform the less than operation", function() {
    expect(4).toBeLessThan(5);
  });
});

Included matchers

toMatch

describe("the toMatch Matcher", function() {
  it("should be able to match the value with a regular expression",
    function() {
      expect("foo bar baz").toMatch(/bar/);
  });
});

Custom matchers

var customMathers = {
  // factory constructor
  toBeMultipleOf: function (util, customEqualityTester) {
    return {
      compare: function(actual, expected) {
        var result = {
          pass: ((actual % expected) == 0)
        }
        if (!result.pass) {
          result.message = "Expected " + actual +
            " to be multiple of " + expected + ", but it isn't";
        }
        return result;
      }
    }
  }
};

Insieme a compare si può specificare negativeCompare nel caso in cui l'utilizzo di not si reputi insufficente.

Custom matchers...

  beforeEach(function() {
    jasmine.addMatchers(customMathers);
  });


  ....
  expect(6).toBeMultipleOf(3);

Esempio 04: Jasmine spies

Person.js

var Person = function() {};

Person.prototype.sayHello = function() {
  return "Hello";
};

Person.prototype.helloSomeone = function(toGreet) {
  return this.sayHello() + " " + toGreet;
};

Call a fake sayHello() method

it("calls the sayHello() dummy function", function() {
  var fakePerson = new Person();

  spyOn(fakePerson, "sayHello");

  fakePerson.helloSomeone("world");
  expect(fakePerson.sayHello).toHaveBeenCalled();
  expect(fakePerson.helloSomeone("world")).toEqual("undefined world");
});

Call a fake sayHello() but propagete to the real sayHello()

it("calls the sayHello() real function but tracks the call", function() {
  var fakePerson = new Person();

  spyOn(fakePerson, "sayHello").and.callThrough();

  fakePerson.helloSomeone("world");
  expect(fakePerson.sayHello).toHaveBeenCalled();
  expect(fakePerson.helloSomeone("world")).toEqual("Hello world");
});

Check passed-in parameters

it("greets the world", function() {
  var fakePerson = new Person();

  spyOn(fakePerson, "helloSomeone");

  fakePerson.helloSomeone("world");
  expect(fakePerson.helloSomeone).toHaveBeenCalledWith("world");
  expect(fakePerson.helloSomeone).not.toHaveBeenCalledWith("foo");
});

Spy on _sayHello() and return a fixed value (stub)

it("says hello with fixed value", function() {
  var fakePerson = new Person();
  fakePerson.sayHello = jasmine.createSpy('"Say hello" spy')
  .and.returnValue("Super hello");

  fakePerson.helloSomeone("world");
  expect(fakePerson.sayHello).toHaveBeenCalled();
  expect(fakePerson.helloSomeone("world")).toEqual("Super hello world");
});

Spy on _sayHello() and call a fake function

it("says hello with a fake function", function() {
  var fakePerson = new Person();
  fakePerson.sayHello = jasmine.createSpy('"Say hello" spy')
  .and.callFake(function() {
    return "Buongiorno"
  });

  fakePerson.helloSomeone("mondo");
  expect(fakePerson.sayHello).toHaveBeenCalled();
  expect(fakePerson.helloSomeone("mondo")).toEqual("Buongiorno mondo");
});

Lezione 01 Introduzione al testing in javascript Alca Società Cooperativa http://alcacoop.it Released under CC BY-NC-SA 3.0