jasmine/spec/core/ClearStackSpec.js

describe("ClearStack", function() {
  it("works in an integrationy way", function(done) {
    var clearStack = jasmineUnderTest.getClearStack(jasmineUnderTest.getGlobal());

    clearStack(function() {
      done();
    });
  });

  it("uses setImmediate when available", function() {
    var setImmediate = jasmine.createSpy('setImmediate').and.callFake(function(fn) { fn() }),
        global = { setImmediate: setImmediate },
        clearStack = jasmineUnderTest.getClearStack(global),
        called = false;

    clearStack(function() {
      called = true;
    });

    expect(called).toBe(true);
    expect(setImmediate).toHaveBeenCalled();
  });

  it("uses setTimeout instead of setImmediate every 10 calls to make sure we release the CPU", function() {
    var setImmediate = jasmine.createSpy('setImmediate'),
        setTimeout = jasmine.createSpy('setTimeout'),
        global = { setImmediate: setImmediate, setTimeout: setTimeout },
        clearStack = jasmineUnderTest.getClearStack(global);

    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });

    expect(setImmediate).toHaveBeenCalled();
    expect(setTimeout).not.toHaveBeenCalled();

    clearStack(function() { });
    expect(setImmediate.calls.count()).toEqual(9);
    expect(setTimeout.calls.count()).toEqual(1);

    clearStack(function() { });
    expect(setImmediate.calls.count()).toEqual(10);
    expect(setTimeout.calls.count()).toEqual(1);
  });

  it("uses MessageChannels when available", function() {
    var fakeChannel = {
          port1: {},
          port2: { postMessage: function() { fakeChannel.port1.onmessage(); } }
        },
        global = { MessageChannel: function() { return fakeChannel; } },
        clearStack = jasmineUnderTest.getClearStack(global),
        called = false;

    clearStack(function() {
      called = true;
    });

    expect(called).toBe(true);
  });

  it("uses setTimeout instead of MessageChannel every 10 calls to make sure we release the CPU", function() {
    var fakeChannel = {
          port1: {},
          port2: {
            postMessage: jasmine.createSpy('postMessage').and.callFake(function() {
              fakeChannel.port1.onmessage();
            })
          }
        },
        setTimeout = jasmine.createSpy('setTimeout'),
        global = { MessageChannel: function() { return fakeChannel; }, setTimeout: setTimeout },
        clearStack = jasmineUnderTest.getClearStack(global);

    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });
    clearStack(function() { });

    expect(fakeChannel.port2.postMessage).toHaveBeenCalled();
    expect(setTimeout).not.toHaveBeenCalled();

    clearStack(function() { });
    expect(fakeChannel.port2.postMessage.calls.count()).toEqual(9);
    expect(setTimeout.calls.count()).toEqual(1);

    clearStack(function() { });
    expect(fakeChannel.port2.postMessage.calls.count()).toEqual(10);
    expect(setTimeout.calls.count()).toEqual(1);
  });

  it("calls setTimeout when onmessage is called recursively", function() {
    var fakeChannel = {
          port1: {},
          port2: { postMessage: function() { fakeChannel.port1.onmessage(); } }
        },
        setTimeout = jasmine.createSpy('setTimeout'),
        global = {
          MessageChannel: function() { return fakeChannel; },
          setTimeout: setTimeout,
        },
        clearStack = jasmineUnderTest.getClearStack(global),
        fn = jasmine.createSpy("second clearStack function");

    clearStack(function() {
      clearStack(fn);
    });

    expect(fn).not.toHaveBeenCalled();
    expect(setTimeout).toHaveBeenCalledWith(fn, 0);
  });

  it("falls back to setTimeout", function() {
    var setTimeout = jasmine.createSpy('setTimeout').and.callFake(function(fn) { fn() }),
        global = { setTimeout: setTimeout },
        clearStack = jasmineUnderTest.getClearStack(global),
        called = false;

    clearStack(function() {
      called = true;
    });

    expect(called).toBe(true);
    expect(setTimeout).toHaveBeenCalledWith(jasmine.any(Function), 0);
  });
});