Bug 977588 - [Dialer] The Active call screen does not have the option to place calls on hold.

Hi @DouglasSherk , I have included a new test (to be pushed into this PR) for the toggleOnHold() function which is the listener invoked when the hold button is pressed.

I did not include any new tests for the mergeButton click event listener since it just calls CallsHandler.mergeCalls() function which is already tested by https://github.com/mozilla-b2g/gaia/pull/22348/files#diff-4691c1b55512f896e6453a62dc49ca10R1550

Was this what you were referring to? Or would you like us to dispatch the click event and spy if those methods are really invoked? I am not aware of any progress regarding the inclusion of integration tests for the callscreen app which would be probably the way to properly include those tests ;) Thanks!