Output more debugging info if cache constraint fails to assert

Author: Toflar

src/Test/PHPUnit/AbstractCacheConstraintTrait.php

@@ -54,6 +54,14 @@ public function matches($other)
                 $message .= sprintf("\nStatus code of response is %s.", $other->getStatusCode());
             }
 
+            $message .= "\nThe response headers are:\n\n";
+
+            foreach ($other->getHeaders() as $name => $values) {
+                $message .=  $name . ': ' . implode(', ', $values);
+            }
+
+            $message .= sprintf("\nThe response body is:\n\n %s", $other->getBody()->rewind()->getContents());
+
             throw new \RuntimeException($message);
         }