Validate generated Cobertura XML against DTD in tests

Author: sebastianbergmann

tests/tests/Report/CoberturaTest.php

@@ -9,6 +9,14 @@
  */
 namespace SebastianBergmann\CodeCoverage\Report;
 
+use const PHP_EOL;
+use function libxml_clear_errors;
+use function libxml_get_errors;
+use function libxml_use_internal_errors;
+use function sprintf;
+use function str_replace;
+use function trim;
+use DOMDocument;
 use PHPUnit\Framework\Attributes\CoversClass;
 use SebastianBergmann\CodeCoverage\TestCase;
 use SebastianBergmann\CodeCoverage\Util\Xml;
@@ -21,7 +29,7 @@ public function testLineCoverageForBankAccountTest(): void
     {
         $cobertura = new Cobertura;
 
-        $this->assertStringMatchesFormatFile(
+        $this->assertAndValidate(
             TEST_FILES_PATH . 'Report/Cobertura/BankAccount-line.xml',
             $cobertura->process($this->getLineCoverageForBankAccount()->getReport(), null),
         );
@@ -31,7 +39,7 @@ public function testPathCoverageForBankAccountTest(): void
     {
         $cobertura = new Cobertura;
 
-        $this->assertStringMatchesFormatFile(
+        $this->assertAndValidate(
             TEST_FILES_PATH . 'Report/Cobertura/BankAccount-path.xml',
             $cobertura->process($this->getPathCoverageForBankAccount()->getReport(), null),
         );
@@ -41,7 +49,7 @@ public function testCoberturaForFileWithIgnoredLines(): void
     {
         $cobertura = new Cobertura;
 
-        $this->assertStringMatchesFormatFile(
+        $this->assertAndValidate(
             TEST_FILES_PATH . 'Report/Cobertura/ignored-lines.xml',
             $cobertura->process($this->getCoverageForFileWithIgnoredLines()->getReport()),
         );
@@ -51,7 +59,7 @@ public function testCoberturaForClassWithAnonymousFunction(): void
     {
         $cobertura = new Cobertura;
 
-        $this->assertStringMatchesFormatFile(
+        $this->assertAndValidate(
             TEST_FILES_PATH . 'Report/Cobertura/class-with-anonymous-function.xml',
             $cobertura->process($this->getCoverageForClassWithAnonymousFunction()->getReport()),
         );
@@ -61,9 +69,49 @@ public function testCoberturaForClassAndOutsideFunction(): void
     {
         $cobertura = new Cobertura;
 
-        $this->assertStringMatchesFormatFile(
+        $this->assertAndValidate(
             TEST_FILES_PATH . 'Report/Cobertura/class-with-outside-function.xml',
             $cobertura->process($this->getCoverageForClassWithOutsideFunction()->getReport()),
         );
     }
+
+    /**
+     * @param non-empty-string $expectationFile
+     * @param non-empty-string $coberturaXml
+     */
+    private function assertAndValidate(string $expectationFile, string $coberturaXml): void
+    {
+        $this->assertStringMatchesFormatFile($expectationFile, $coberturaXml);
+
+        $coberturaXml = str_replace(
+            '<?xml version="1.0" encoding="UTF-8"?>',
+            '<?xml version="1.0" encoding="UTF-8"?>' . "\n" . '<!DOCTYPE coverage SYSTEM "' . __DIR__ . '/../../_files/Report/Cobertura/coverage-04.dtd">',
+            $coberturaXml,
+        );
+
+        libxml_use_internal_errors(true);
+
+        $document = new DOMDocument;
+        $document->loadXML($coberturaXml);
+
+        if (!$document->validate()) {
+            $buffer = 'Generated XML document does not validate against Cobertura DTD:' . PHP_EOL . PHP_EOL;
+
+            foreach (libxml_get_errors() as $error) {
+                $buffer .= sprintf(
+                    '- Line %d: %s' . PHP_EOL,
+                    $error->line,
+                    trim($error->message),
+                );
+            }
+
+            $buffer .= PHP_EOL;
+        }
+
+        libxml_clear_errors();
+
+        if (isset($buffer)) {
+            $this->fail($buffer);
+        }
+    }
 }