diff --git a/mlir/unittests/TableGen/OpBuildGen.cpp b/mlir/unittests/TableGen/OpBuildGen.cpp
--- a/mlir/unittests/TableGen/OpBuildGen.cpp
+++ b/mlir/unittests/TableGen/OpBuildGen.cpp
@@ -19,6 +19,8 @@
 #include "gmock/gmock.h"
 #include <vector>
 
+using namespace mlir::test;
+
 namespace mlir {
 
 //===----------------------------------------------------------------------===//