remove check for keys

Author: taylorotwell

src/Illuminate/Foundation/Testing/TestResponse.php

@@ -552,7 +552,6 @@ protected function jsonSearchStrings($key, $value)
         $needle = substr(json_encode([$key => $value]), 1, -1);
 
         return [
-            $needle.':',
             $needle.']',
             $needle.'}',
             $needle.',',

tests/Foundation/FoundationTestResponseTest.php

@@ -167,8 +167,6 @@ public function testAssertJsonFragment()
 
         $response = TestResponse::fromBaseResponse(new Response(new JsonSerializableMixedResourcesStub));
 
-        $response->assertJsonFragment(['foobar']);
-
         $response->assertJsonFragment(['foo' => 'bar']);
 
         $response->assertJsonFragment(['foobar_foo' => 'foo']);