Fix flaky should_include_code_in_json_when_code_is_not_null

Author: pem70

swagger/swagger-invocation/invocation-core/src/test/java/org/apache/servicecomb/swagger/invocation/exception/CommonExceptionDataTest.java

@@ -36,7 +36,11 @@ void should_not_include_code_in_json_when_code_is_null() {
   void should_include_code_in_json_when_code_is_not_null() {
     CommonExceptionData data = new CommonExceptionData("code", "msg");
 
-    assertThat(Json.encode(data)).isEqualTo("{\"code\":\"code\",\"message\":\"msg\"}");
+    String json = Json.encode(data);
+    @SuppressWarnings("unchecked")
+    Map<String, Object> obj = Json.decodeValue(json, Map.class);
+
+    assertThat(obj).containsEntry("code", "code").containsEntry("message", "msg").hasSize(2);
   }
 
   @Test