[Performance] Reduce repetitive FileSystem::read() on AbstractRectorT…

…estCase (#5511)

src/Testing/PHPUnit/AbstractRectorTestCase.php

@@ -161,7 +161,7 @@ protected function doTestFile(string $fixtureFilePath): void
         // write temp file
         FileSystem::write($inputFilePath, $inputFileContents);
 
-        $this->doTestFileMatchesExpectedContent($inputFilePath, $expectedFileContents, $fixtureFilePath);
+        $this->doTestFileMatchesExpectedContent($inputFilePath, $inputFileContents, $expectedFileContents, $fixtureFilePath);
     }
 
     protected function forgetRectorsRulesAndCollectors(): void
@@ -210,14 +210,12 @@ private function includePreloadFilesAndScoperAutoload(): void
 
     private function doTestFileMatchesExpectedContent(
         string $originalFilePath,
+        string $inputFileContents,
         string $expectedFileContents,
         string $fixtureFilePath
     ): void {
         SimpleParameterProvider::setParameter(Option::SOURCE, [$originalFilePath]);
 
-        // the original file content must be loaded first
-        $originalFileContent = FileSystem::read($originalFilePath);
-
         // the file is now changed (if any rule matches)
         $rectorTestResult = $this->processFilePath($originalFilePath);
 
@@ -239,7 +237,7 @@ private function doTestFileMatchesExpectedContent(
         try {
             $this->assertSame($expectedFileContents, $changedContents, $failureMessage);
         } catch (ExpectationFailedException) {
-            FixtureFileUpdater::updateFixtureContent($originalFileContent, $changedContents, $fixtureFilePath);
+            FixtureFileUpdater::updateFixtureContent($inputFileContents, $changedContents, $fixtureFilePath);
 
             // if not exact match, check the regex version (useful for generated hashes/uuids in the code)
             $this->assertStringMatchesFormat($expectedFileContents, $changedContents, $failureMessage);