Conditionally ignore individual tests with Karma / Jasmine

The most simple solution that I see is to override global functions describe and it to make them accept third optional argument, which has to be a boolean or a function returning a boolean - to tell whether or not current suite/spec should be executed. When overriding we should check if this third optional arguments resolves to true, and if it does, then we call xdescribe/xit (or ddescribe/iit depending on Jasmine version), which are Jasmine's methods to skip suite/spec, istead of original describe/it. This block has to be executed before the tests, but after Jasmine is included to the page. In Karma just move this code to a file and include it before test files in karma.conf.js. Here is the code:

(function (global) {

  // save references to original methods
  var _super = {
    describe: global.describe,
    it: global.it
  };

  // override, take third optional "disable"
  global.describe = function (name, fn, disable) {
    var disabled = disable;
    if (typeof disable === 'function') {
      disabled = disable();
    }

    // if should be disabled - call "xdescribe" (or "ddescribe")
    if (disable) {
      return global.xdescribe.apply(this, arguments);
    }

    // otherwise call original "describe"
    return _super.describe.apply(this, arguments);
  };

  // override, take third optional "disable"
  global.it = function (name, fn, disable) {
    var disabled = disable;
    if (typeof disable === 'function') {
      disabled = disable();
    }

    // if should be disabled - call "xit" (or "iit")
    if (disable) {
      return global.xit.apply(this, arguments);
    }

    // otherwise call original "it"
    return _super.it.apply(this, arguments);
  };

}(window));

And usage example:

describe('foo', function () {

  it('should foo 1 ', function () {
    expect(true).toBe(true);
  });

  it('should foo 2', function () {
    expect(true).toBe(true);
  }); 

}, true); // disable suite

describe('bar', function () {

  it('should bar 1 ', function () {
    expect(true).toBe(true);
  });

  it('should bar 2', function () {
    expect(true).toBe(true);
  }, function () {
    return true; // disable spec
  });

}); 

See a working example here

I've also stumbled upon this issue where the idea was to add a chain method .when() for describe and it, which will do pretty much the same I've described above. It may look nicer but is a bit harder to implement.

describe('foo', function () {

  it('bar', function () {
    // ...
  }).when(anything);      

}).when(something);

If you are really interested in this second approach, I'll be happy to play with it a little bit more and try to implement chain .when().

Update:

Jasmine uses third argument as a timeout option (see docs), so my code sample is replacing this feature, which is not ok. I like @milanlempera and @MarcoCI answers better, mine seems kinda hacky and not intuitive. I'll try to update my solution anyways soon not to break compatibilty with Jasmine default features.

Jasmine supports a pending() function.

If you call pending() anywhere in the spec body, no matter the expectations, the spec will be marked pending.

You can call pending() directly in test, or in some other function called from test.

function skipIfCondition() {
  pending();
}

function someSkipCheck() {
  return true;
}

describe("test", function() {
  it("call pending directly by condition", function() {
    if (someSkipCheck()) {
      pending();
    }

    expect(1).toBe(2);
  });

  it("call conditionally skip function", function() {
    skipIfCondition();

    expect(1).toBe(3);
  });

  it("is executed", function() {
    expect(1).toBe(1);
  });

});

working example here: http://plnkr.co/edit/JZtAKALK9wi5PdIkbw8r?p=preview

I think it is purest solution. In test results you can see count of finished and skipped tests.