diff --git a/llvm/utils/gn/secondary/clang/unittests/Serialization/BUILD.gn b/llvm/utils/gn/secondary/clang/unittests/Serialization/BUILD.gn
index f2ad1dcdacc7..f8474c13f048 100644
--- a/llvm/utils/gn/secondary/clang/unittests/Serialization/BUILD.gn
+++ b/llvm/utils/gn/secondary/clang/unittests/Serialization/BUILD.gn
@@ -18,6 +18,7 @@ unittest("SerializationTests") {
     "InMemoryModuleCacheTest.cpp",
     "LoadSpecLazilyTest.cpp",
     "ModuleCacheTest.cpp",
+    "NamespaceLookupTest.cpp",
     "NoCommentsTest.cpp",
     "PreambleInNamedModulesTest.cpp",
     "SourceLocationEncodingTest.cpp",