Upgrade docs for v3.1 (#6335)

Co-authored-by: zxyfaxcn <[email protected]>
Co-authored-by: Lu Fei <[email protected]>

Author: 3 people

src/Http/TestResponse.php

@@ -549,9 +549,10 @@ public function decodeResponseJson()
         $decodedResponse = $testJson->json();
 
         if (is_null($decodedResponse) || $decodedResponse === false) {
-            if ($this->exception ?? null) {
-                throw $this->exception;
-            }
+            $exception = $this->exception ?? null;
+
+            $exception && throw $exception;
+
             PHPUnit::fail('Invalid JSON was returned from the route.');
         }