diff --git a/test/helpers.hpp b/test/helpers.hpp
index 1ac21ca..10e8cd7 100644
--- a/test/helpers.hpp
+++ b/test/helpers.hpp
@@ -9,6 +9,9 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+namespace pid_control
+{
+
 using ::testing::_;
 using ::testing::Invoke;
 using ::testing::IsNull;
@@ -67,3 +70,5 @@
 
     return;
 }
+
+} // namespace pid_control