Unit testing watchers in angular js controller

Question

How can this snippet code be unit tested using jasmine ?

    $scope.profileObject = ProfilesSharedObject;

$scope.$watch("profileObject.startDate", function() {
    var startDate = $scope.profileObject.startDate._d;
    var endDate = $scope.profileObject.endDate._d;

    var newStartDate = moment(startDate).format("YYYY-MM-DD");
    var newEndDate = moment(endDate).format("YYYY-MM-DD");

    $scope.startDate = moment(startDate).format("MM/DD");
    $scope.endDate = moment(endDate).format("MM/DD/YYYY");

    $scope.getSleepData(newStartDate, newEndDate);
});

where ProfileSharedObject is a angular js service

Answer 1

Watch listeners are evaluated at every digest cycle. Usually that happens automagically, but while unit testing you need to manually trigger it:

it('should update the start date', function() {
    // Arrange
    ProfileSharedObjectMock.startDate = new Date(2013, 0, 1);

    // Act
    $scope.$digest();

    // Assert
    expect($scope.startDate).toEqual(new Date(2013, 0, 1));
  });

I've created a Plunker script so you can see the whole test suite working.