scope.$watch not called in directive when unit testing

Question

Problem I am testing a directive. The directive has a watch on a scope variable, but the watch is never called. Putting the `$watch` call directly inside the unit test works. Why isn't the `$watch` in the directive not called? Thanks! Details Here's my original test. The directive has a watch in it, looking at `'reEvalCreateDate'`. It's never called and the date string is always empty. Test with no watch statement in it ``` it('should inject a date string', function() { scope.reEvalCreateDate = reEvalCreateDateAsNumber; expect(elm.text()).toBe(''); scope.$digest(); expect(elm.text()).toBe(new Date(reEvalCreateDateAsNumber).toUTCString()); }); ``` As a test, I put the watch within the unit test. It is correctly called and the test passes. Source (modified to put the watch in the test itself) ``` it('should inject a date string', function() { scope.$watch('reEvalCreateDate', function(newValue, oldValue) { var date = new Date(newValue); scope.dateString = date.toUTCString(); dump(scope.d…

Accepted Answer

I just ran into a similar issue while testing a directive with isolate scope.

The reason it wasn't called is that `$digest` "processes all of the watchers of the current scope and its children" (http://docs.angularjs.org/api/ng.$rootScope.Scope). Now, you would think that a directive's bi-directionally bound variables (defined with "=") would be watching the test's scope, but I found that my `$watch` wasn't being called. Is this a bug in angular?

My solution was to wrap all the testing code after the `scope.$digest()` into a `$timeout`, e.g:

```
inject(function($timeout) {
  // change test scope variable
  scope.$digest();
  $timeout(function() {
    // assertions
    expect(...)
  }, 0);
}
```

Edit: Also see Unit testing an AngularJS directive that watches an an attribute with isolate scope

scope.$watch not called in directive when unit testing

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