Do not suppress warning messages

[selfsimilar]

This is a fix for #293. Warnings should not be suppressed, unless you also suppress the output on STDERR.

[abobija]

Lgtm. Not sure why this warning was initially suppressed.

[hamidhaghdoost]

I'm working on a codebase with tons of tests, and my pipeline was consistently failing with a 1 exit code, without any error or warning. After a couple of days of debugging, I realized the issue: "A test file without implementation".

I'm not sure why this piece of code was being suppressed, but it should be fixed.

[edh649]

I would also like to see this merged, it's affected by CI pipeline too and makes it very difficult to work out why CI is failing despite all tests passing.

[yuraplohov]

I am also waiting for this fix. I'm facing the same problem with CI piplene that falls without errors. And it also took a while to figure out the reason. The warning "No tests found in class" should not be suppressed. Until this is fixed, I have to use kludges.

[jaymoh]

I would also like to see this merged. I'm aware the contributors have a lot of work, so I will be refreshing this page every week, to monitor progress.

[Ghustavh97]

Any updates on this PR? I think suppressing messages that generate an exit code greater than 0 is not a good idea.

[darkbasic]

Hi, thanks for the PR. I've tried to patch DefaultPrinter.php but it still returns 1 with no warnings visible in the output. Any idea what might cause it?