RxJS version:
master

Code to reproduce:
Run browser test

Additional information:
It seems some of test cases are having incorrect fixture setup. I can't even tell what is incorrect at this moment - it could be test case was composed incorrectly, or browser test setup might wrong. It creates intermittent test failure on browsers such as causing

• test completes too early without executing all suite
• some test causes test runner hangs without timeout, infinitely stays there

below screenshot illustrates first cases I could see, only 1/10 of tests are executed but marked as 100%.

Note this is very intermittent issue and sometimes it occurs quite easily but sometimes never occurs. to improve stability of tests, this need to be addressed and fixed.

Q: What's the difference between #1660?
: #1660 is more about issue of connection to browser testing itself, which cannot connect or either disconnect quite frequently prevents test run reliably. I have tested browserStack and it indeed works more reliably, but due to issue in our test cases it now 'reliably fails' on several browsers.