I believe the error is stating that : The test module is implicitly importing your main module's bridging header. You don't need to import it. Everything is OK.
Everything is OK now, but it won't be OK later because this "implicit" import will disappear soon (deprecated) and thus, it's not gonna be OK anymore.
In order to stay OK, you should "explicitly" import your main module's bridging header in your test module's bridging header.
So, in your MyApp-Tests-BridgingHeader.h you should have :
//
// Use this file to import your target's public headers that you would like to expose to Swift.
//
#import "MyApp-Bridging-Header.h"
...
Then, Everything will be OK and will stay OK :)