SEP1 tests failed on Firefox

### What version are you using?
Latest master branch. Git cloned and build.

### What did you do?
Developed a SEP1 server with Java.
Use http://localhost:8080 as the home domain.
Run sep-1 test. 


### What did you expect to see?
SEP-1 tests succeed.

### What did you see instead?
After clicking `Run Tests`, FireFox returns to restart the tests. 

Chromium works fine.



