diff --git a/test/pid_fancontroller_unittest.cpp b/test/pid_fancontroller_unittest.cpp
index abf9aaa..866b743 100644
--- a/test/pid_fancontroller_unittest.cpp
+++ b/test/pid_fancontroller_unittest.cpp
@@ -9,6 +9,11 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+namespace pid_control
+{
+namespace
+{
+
 using ::testing::_;
 using ::testing::DoubleEq;
 using ::testing::Invoke;
@@ -245,3 +250,6 @@
     // to the sensors.
     p->outputProc(percent);
 }
+
+} // namespace
+} // namespace pid_control