:green_heart: fix unit test

tests/src/unit-bson.cpp

diff --git a/tests/src/unit-bson.cpp b/tests/src/unit-bson.cpp
index a231c8c..fa07e9d 100644
--- a/tests/src/unit-bson.cpp
+++ b/tests/src/unit-bson.cpp
@@ -10,6 +10,9 @@
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
+#ifdef JSON_TEST_NO_GLOBAL_UDLS
+using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
+#endif
 
 #include <fstream>
 #include <sstream>