Spotted by @teropa and confirmed on my side in the ng2 directives for Bootstrap project (see: ng-bootstrap/ng-bootstrap#115):

I'm getting errors about platform directives like ng-for when using TestComponentBuilder. Seems like they're not "ambient" in the unit tests like they are during normal execution. I can fix it by including CORE_DIRECTIVES in the component, but that seems backward. Any ideas how to make them available?