[BUGFIX] Normalize CodeCoverage objects

phpunit/php-code-coverage >= 9.2 expects an option "fromTestcase" in its test data.

src/PhpunitMerger/Command/CoverageCommand.php

@@ -65,6 +65,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             if (!$coverage instanceof CodeCoverage) {
                 throw new \RuntimeException($file->getRealPath() . ' doesn\'t return a valid ' . CodeCoverage::class . ' object!');
             }
+            $this->normalizeCoverage($coverage);
             $codeCoverage->merge($coverage);
         }
 
@@ -91,6 +92,15 @@ private function getCodeCoverage()
         return new CodeCoverage($driver, $filter);
     }
 
+    private function normalizeCoverage(CodeCoverage $coverage)
+    {
+        $tests = $coverage->getTests();
+        foreach ($tests as &$test) {
+            $test['fromTestcase'] = $test['fromTestcase'] ?? false;
+        }
+        $coverage->setTests($tests);
+    }
+
     private function writeCodeCoverage(CodeCoverage $codeCoverage, OutputInterface $output, $file = null)
     {
         $writer = new Clover();