Modal transition not supported in test mode (Karma & Angular 2)

I try to test my code with Karma in an Angular 2 project. The project use Semantic UI, with the default theme.

When I launch the "ng test" command to test my application, the Chrome console display the following error :

Transition: Element is no longer attached to DOM. Unable to animate. Use silent setting to surpress this warning in production. Vertical Flip in div.ui.modal

It seems the transition to open a modal is not supported in test mode.

Does somebody has any idea to that ?

Thanx