ClassMapGeneratorTest: add test with consecutive duplicate heredoc markers

... as well as a test with heredoc markers with only a newline character between the start and end marker.

tests/Composer/Test/Autoload/ClassMapGeneratorTest.php

@@ -55,6 +55,9 @@ class ClassMapGeneratorTest extends TestCase
             'Foo\\LargeGap' => realpath(__DIR__) . '/Fixtures/classmap/LargeGap.php',
             'Foo\\MissingSpace' => realpath(__DIR__) . '/Fixtures/classmap/MissingSpace.php',
             'Foo\\StripNoise' => realpath(__DIR__) . '/Fixtures/classmap/StripNoise.php',
+            'Foo\\First' => realpath(__DIR__) . '/Fixtures/classmap/StripNoise.php',
+            'Foo\\Second' => realpath(__DIR__) . '/Fixtures/classmap/StripNoise.php',
+            'Foo\\Third' => realpath(__DIR__) . '/Fixtures/classmap/StripNoise.php',
             'Foo\\SlashedA' => realpath(__DIR__) . '/Fixtures/classmap/BackslashLineEndingString.php',
             'Foo\\SlashedB' => realpath(__DIR__) . '/Fixtures/classmap/BackslashLineEndingString.php',
             'Unicode\\↑\\↑' => realpath(__DIR__) . '/Fixtures/classmap/Unicode.php',

tests/Composer/Test/Autoload/Fixtures/classmap/StripNoise.php

@@ -90,3 +90,27 @@ NOWDOCTABBED . <<<'NOWDOCPHP73'
         return 'class FailSimpleString {}';
     }
 }
+
+// Issue #10067.
+abstract class First {
+    public function heredocDuplicateMarker(): void {
+        echo <<<DUPLICATE_MARKER
+
+        DUPLICATE_MARKER;
+    }
+}
+
+abstract class Second extends First {
+    public function heredocDuplicateMarker(): void {
+        echo <<<DUPLICATE_MARKER
+
+        DUPLICATE_MARKER;
+    }
+}
+
+abstract class Third extends First {
+    public function heredocMarkersOnlyWhitespaceBetween(): void {
+        echo <<<DUPLICATE_MARKER
+DUPLICATE_MARKER;
+    }
+}