Add $schema to infection.json5.dist, exclude files that breaks PHPUnit execution with Infection

[maks-rafalko]

See #5788 (comment) for the detailed explanation about what is going on and why it's needed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.17%. Comparing base (b18d5f2) to head (72e01df).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #5792   +/-   ##
=========================================
  Coverage     90.17%   90.17%           
  Complexity     6582     6582           
=========================================
  Files           693      693           
  Lines         19940    19940           
=========================================
  Hits          17980    17980           
  Misses         1960     1960           

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[staabm]

Thank you 🙏

[sebastianbergmann]

I am thankful for your work, @maks-rafalko and @staabm, but I am still seeing issues such as this basically everywhere I look:

The Finished class has a public method named test.

Infection's PublicVisibility mutator replaces public and protected and Infection then claims that this mutation survived, as can be seen in this screenshot:

However, when I perform this mutation manually ...

diff --git a/src/Event/Events/Test/Lifecycle/Finished.php b/src/Event/Events/Test/Lifecycle/Finished.php
index 72032cf71..ae75d35c1 100644
--- a/src/Event/Events/Test/Lifecycle/Finished.php
+++ b/src/Event/Events/Test/Lifecycle/Finished.php
@@ -37,7 +37,7 @@ public function telemetryInfo(): Telemetry\Info
         return $this->telemetryInfo;
     }
 
-    public function test(): Code\Test
+    protected function test(): Code\Test
     {
         return $this->test;
     }

... and try to run PHPUnit's test suite then I get this error:

$ ./phpunit --testsuite unit
PHPUnit 11.1-gb18d5f2fe3 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.4
Configuration: /usr/local/src/phpunit/phpunit.xml

.

An error occurred inside PHPUnit.

Message:  Call to protected method PHPUnit\Event\Test\Finished::test() from scope PHPUnit\Runner\ResultCache\ResultCacheHandler
Location: /usr/local/src/phpunit/src/Runner/ResultCache/ResultCacheHandler.php:119

#0 /usr/local/src/phpunit/src/Runner/ResultCache/Subscriber/TestFinishedSubscriber.php(27): PHPUnit\Runner\ResultCache\ResultCacheHandler->testFinished()
#1 /usr/local/src/phpunit/src/Event/Dispatcher/DirectDispatcher.php(102): PHPUnit\Runner\ResultCache\TestFinishedSubscriber->notify()
#2 /usr/local/src/phpunit/src/Event/Dispatcher/DeferringDispatcher.php(45): PHPUnit\Event\DirectDispatcher->dispatch()
#3 /usr/local/src/phpunit/src/Event/Emitter/DispatchingEmitter.php(962): PHPUnit\Event\DeferringDispatcher->dispatch()
#4 /usr/local/src/phpunit/src/Framework/TestRunner.php(235): PHPUnit\Event\DispatchingEmitter->testFinished()
#5 /usr/local/src/phpunit/src/Framework/TestCase.php(337): PHPUnit\Framework\TestRunner->run()
#6 /usr/local/src/phpunit/src/Framework/TestSuite.php(369): PHPUnit\Framework\TestCase->run()
#7 /usr/local/src/phpunit/src/Framework/TestSuite.php(369): PHPUnit\Framework\TestSuite->run()
#8 /usr/local/src/phpunit/src/Framework/TestSuite.php(369): PHPUnit\Framework\TestSuite->run()
#9 /usr/local/src/phpunit/src/TextUI/TestRunner.php(62): PHPUnit\Framework\TestSuite->run()
#10 /usr/local/src/phpunit/src/TextUI/Application.php(200): PHPUnit\TextUI\TestRunner->run()
#11 /usr/local/src/phpunit/phpunit(104): PHPUnit\TextUI\Application->run()
#12 {main}

The mutation causes an error in PHPUnit's test runner that is not specific to a single test.

Sure, we can exclude mutators and/or source files. But I doubt that this will lead to a useful report. I fear that we must accept the fact that mutating the test (framework|runner) while running its test is an edge case that neither of us should worry about: Infection should not be adapted to cater to the mutation testing of PHPUnit, nor should PHPUnit be adapted so that mutation testing can be performed on it.

Maybe I am just too pessimistic here, but, as always, I love to be proven wrong.

In the near future (days/weeks, not months), I will add Infection to the dependencies of PHPUnit (see #5788 (comment)). This should be more straightforward.

[staabm]

Lets let this sink for a while and look into what solutions we can find :-)