message: white_check_mark: added missing tests found by mutate++
diff: @@ -596,6 +596,32 @@ TEST_CASE("parser class")
  "missing or wrong low surrogate");
  }
  + SECTION("tests found by mutate++")
  + {
  + // test case to make sure no comma preceeds the first key
  + CHECK_THROWS_AS(json::parser("{,\"key\": false}").parse(), std::invalid_argument);
  + // test case to make sure an object is properly closed
  + CHECK_THROWS_AS(json::parser("[{\"key\": false true]").parse(), std::invalid_argument);
  +
  + // test case to make sure the callback is properly evaluated after reading a key
  + {
  + json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed)
  + {
  + if (event == json::parse_event_t::key)
  + {
  + return false;
  + }
  + else
  + {
  + return true;
  + }
  + };
  +
  + json x = json::parse("{\"key\": false}", cb);
  + CHECK(x == json::object());
  + }
  + }
  +
  SECTION("callback function")
  {
  auto s_object = R"(
  