Failed Automation Test does not close the game


after hours of testing I got the automation tests in c++ to work. The last problem I have, is that if a Test fails, the game does not shutdown but runs forever.
Lets say I have only this one line of code, in which I verify if 3 equals 4. This test will obviously fail every time.

TestEqual(FString(TEXT("This test will always fail.")), 3, 4);

The test will run, fail, but then the game continues to run forever.

If I use a test to check if 4 equals 4, like this:

TestEqual(FString(TEXT("This test will always pass.")), 4, 4);

the test is successful and the game closes.

Any ideas how to make sure the game closes after a failed test?

Cheers Meiwen