correctly fail/update the file snapshot assertion when file extensions are different

Author: SjorsO

src/Filesystem.php

@@ -27,6 +27,31 @@ public function has(string $filename): bool
         return file_exists($this->path($filename));
     }
 
+    /**
+     * Get all file names in this directory that have the same name
+     * as $fileName, but have a different file extension
+     * @param string $fileName
+     * @return array
+     */
+    public function getNamesWithDifferentExtension(string $fileName)
+    {
+        $extension = pathinfo($fileName, PATHINFO_EXTENSION);
+
+        $baseName = substr($fileName, 0, strlen($fileName) - strlen($extension) - 1);
+
+        $allNames = scandir($this->basePath);
+
+        $namesWithDifferentExtension = array_filter($allNames, function ($existingName) use ($baseName, $extension) {
+            $existingExtension = pathinfo($existingName, PATHINFO_EXTENSION);
+
+            $existingBaseName = substr($existingName, 0, strlen($existingName) - strlen($existingExtension) - 1);
+
+            return $existingBaseName === $baseName && $existingExtension !== $extension;
+        });
+
+        return array_values($namesWithDifferentExtension);
+    }
+
     public function read(string $filename): string
     {
         return file_get_contents($this->path($filename));

src/MatchesSnapshots.php

@@ -161,6 +161,24 @@ protected function doFileSnapshotAssertion(string $filePath)
 
         $snapshotId = $this->getSnapshotId().'.'.$fileExtension;
 
+        // If $filePath has a different file extension than the snapshot, the test should fail
+        if ($namesWithDifferentExtension = $fileSystem->getNamesWithDifferentExtension($snapshotId)) {
+            // There is always only one existing snapshot with a different extension
+            $existingSnapshotId = $namesWithDifferentExtension[0];
+
+            if ($this->shouldUpdateSnapshots()) {
+                $fileSystem->delete($existingSnapshotId);
+
+                $fileSystem->copy($filePath, $snapshotId);
+
+                return $this->markTestIncomplete("File snapshot updated for {$snapshotId}");
+            }
+
+            $expectedExtension = pathinfo($existingSnapshotId, PATHINFO_EXTENSION);
+
+            return $this->fail("File did not match the snapshot file extension (expected: {$expectedExtension}, was: {$fileExtension})");
+        }
+
         $failedSnapshotId = $snapshotId.'_failed.'.$fileExtension;
 
         if ($fileSystem->has($failedSnapshotId)) {

tests/Integration/MatchesSnapshotTest.php

@@ -165,6 +165,16 @@ public function it_can_mismatch_a_file_snapshot()
         $mockTrait->assertMatchesFileSnapshot(__DIR__.'/stubs/test_files/troubled_man.jpg');
     }
 
+    /** @test */
+    public function it_can_mismatch_a_file_snapshot_with_a_different_extension()
+    {
+        $mockTrait = $this->getMatchesSnapshotMock();
+
+        $this->expectFail($mockTrait);
+
+        $mockTrait->assertMatchesFileSnapshot(__DIR__.'/stubs/test_files/no_man.png');
+    }
+
     /** @test */
     public function it_needs_a_file_extension_to_do_a_file_snapshot_assertion()
     {
@@ -282,6 +292,29 @@ public function it_can_update_a_file_snapshot()
         );
     }
 
+    /** @test */
+    public function it_can_update_a_file_snapshot_with_a_different_extension()
+    {
+        $_SERVER['argv'][] = '--update-snapshots';
+
+        $mockTrait = $this->getMatchesSnapshotMock();
+
+        $this->expectIncompleteMatchesSnapshotTest($mockTrait);
+
+        $oldSnapshot = __DIR__.'/__snapshots__/files/MatchesSnapshotTest__it_can_update_a_file_snapshot_with_a_different_extension__1.jpg';
+
+        $this->assertFileExists($oldSnapshot);
+
+        $mockTrait->assertMatchesFileSnapshot(__DIR__.'/stubs/test_files/no_man.png');
+
+        $this->assertSnapshotMatchesExample(
+            'files/MatchesSnapshotTest__it_can_update_a_file_snapshot_with_a_different_extension__1.png',
+            'file.png'
+        );
+
+        $this->assertFileNotExists($oldSnapshot);
+    }
+
     private function expectIncompleteMatchesSnapshotTest(PHPUnit_Framework_MockObject_MockObject $matchesSnapshotMock)
     {
         $matchesSnapshotMock