2 files changed, 23 insertions, 0 deletions
diff --git a/src/Middleware/ErrorHandler.php b/src/Middleware/ErrorHandler.php
index 9fc34722..29b1fac1 100644
--- a/src/Middleware/ErrorHandler.php
+++ b/src/Middleware/ErrorHandler.php
@@ -48,6 +48,10 @@ class ErrorHandler implements MiddlewareInterface
         $statusCode = $response->getStatusCode();
         $contentType = $response->getHeader('content-type');
         $contentType = array_shift($contentType);
+        if (!$contentType && strpos($response->getBody(), '<html') !== false) {
+            $contentType = 'text/html';
+        }
+
         if (
             $statusCode < 400
             || !$response instanceof Response
diff --git a/tests/Unit/Middleware/ErrorHandlerTest.php b/tests/Unit/Middleware/ErrorHandlerTest.php
index cce752d1..6c37b651 100644
--- a/tests/Unit/Middleware/ErrorHandlerTest.php
+++ b/tests/Unit/Middleware/ErrorHandlerTest.php
@@ -143,4 +143,23 @@ class ErrorHandlerTest extends TestCase
         $return = $errorHandler->process($request, $returnResponseHandler);
         $this->assertEquals($psrResponse, $return);
     }
+
+    /**
+     * @covers \Engelsystem\Middleware\ErrorHandler::process
+     */
+    public function testProcessContentTypeSniffer()
+    {
+        /** @var ServerRequestInterface|MockObject $request */
+        $request = $this->createMock(ServerRequestInterface::class);
+        /** @var TwigLoader|MockObject $twigLoader */
+        $twigLoader = $this->createMock(TwigLoader::class);
+        $response = new Response('<!DOCTYPE html><html><body><h1>Hi!</h1></body></html>', 500);
+        $returnResponseHandler = new ReturnResponseMiddlewareHandler($response);
+
+        /** @var ErrorHandler|MockObject $errorHandler */
+        $errorHandler = new ErrorHandler($twigLoader);
+
+        $return = $errorHandler->process($request, $returnResponseHandler);
+        $this->assertEquals($response, $return);
+    }
 }