jasmine-precondition

example.js

describe('the preCondition instruction', function () {

  var counter1 = 0,
      counter2 = 0,
      interval;

  beforeEach(function(done) {
    interval = setInterval(function(){
      counter1 += 100;
    }, 100);

    preCondition(function() {
      return counter1 >= 500;
    }, done, 100);
  });

  it('should only get executed when counter1 is 500', function (done) {
    expect(counter1).toBe(500);

    preCondition(function() {
      counter2 += 200;
      return counter2 === 1000;
    }, done, 100);
  });

  it('should only get executed when counter2 is 1000', function () {
    expect(counter2).toBe(1000);
  });

  afterEach(function(){
    clearInterval(interval);
  });
});

jasmine-precondition.js

preCondition(condition, done, interval);