Use symfony/process to run isolated tests

[rpkamp]

Fixes #1342

[sebastianbergmann]

Thank you for working on this, @rpkamp. However, this will have to wait until #2015 is implemented.

[codecov-io]

Codecov Report

Merging #3117 into master will increase coverage by 0.33%.
The diff coverage is 92.59%.

@@             Coverage Diff              @@
##             master    #3117      +/-   ##
============================================
+ Coverage     82.28%   82.61%   +0.33%     
+ Complexity     3487     3468      -19     
============================================
  Files           140      140              
  Lines          9211     9154      -57     
============================================
- Hits           7579     7563      -16     
+ Misses         1632     1591      -41

Impacted Files	Coverage Δ	Complexity Δ
src/Util/PHP/WindowsPhpProcess.php	0% <ø> (ø)	1 <0> (-3)	⬇️
src/Util/PHP/DefaultPhpProcess.php	55.26% <90.9%> (+11.17%)	15 <0> (-17)	⬇️
src/Util/PHP/AbstractPhpProcess.php	71.91% <93.75%> (+0.28%)	41 <10> (+1)	⬆️

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[rpkamp]

That's okay. Tests for windows are still failing anyway. Will look at that later.

[rpkamp]

I've checked to see if I could fix the errors in AppVeyor and ran into the following:

C:\phpunit\tests\TextUI\phpt-args.phpt:

The problem here is that the argument supplied in ARGS in the .phpt file is passed with a trailing \n, which doesn't seem to matter on *nix, but on windows, the supplied value is literally help\n, which isn't equal to help, so the test fails. I could change the test to if ($argc > 0 && strpos($argv[1], 'help') === 0) and then it would succeed, but it is a break in functionality that others might run into as well. Not really sure how to correctly solve this without any BC breaks. Input would be appreciated.

C:\phpunit\tests\Regression\GitHub\1348.phpt

This one is even tougher, as symfony/process doesn't use regular STDOUT/STDERR on windows as there are several problematic bugs around it. Instead it redirects all OUT/ERR to files. This means that writing to STDOUT from the test file will not be sent to the terminal, but to the file that STDOUT is redirected to instead. This also a BC break that I don't see a nice way of working around. Again, input would be appreciated.

[rpkamp]

Replaced by #3117