Mocking Angular bootstrap-ui directive for unit tests

I'm trying to write a unit test to ensure that a directive works correctly.

The directive's template includes the Angular bootstrap datepicker, so I would like to be able to mock that.

This question says I should be able to mock directives by creating new directives with the same name using $compileProvider and setting a high priority and terminal to true:

beforeEach(function() {
  inject([
    '$compileProvider',
    function($compileProvider) {
      $compileProvider.directive('datePickerOptions', {
        priority: 100,
        terminal: true,
        template: ''
      });

    $compileProvider.directive('datePickerPopup', {
      priority: 100,
     template: ''
    });
  }]);
});

It also says that you can mock directives by just overriding their factory functions like so:

beforeEach(module(function($provide) {
  $provide.factory('datePickerOptionsDirective', function() {
      return {};
  });
  $provide.factory('datePickerPopupDirective', function() {
      return {};
  });
}));

Neither of these methods are working for me. I'm using Karma unit tests. Any thoughts?