diff --git a/test_common/CMakeLists.txt b/test_common/CMakeLists.txt
index b285d45d..0eee4509 100644
--- a/test_common/CMakeLists.txt
+++ b/test_common/CMakeLists.txt
@@ -2,7 +2,7 @@
 set(HARNESS_COMMON_SOURCES
     harness/threadTesting.cpp
     harness/typeWrappers.cpp
-    harness/mt19937.c
+    harness/mt19937.cpp
     harness/conversions.cpp
     harness/rounding_mode.cpp
     harness/msvc9.c
diff --git a/test_common/harness/mt19937.c b/test_common/harness/mt19937.cpp
similarity index 100%
rename from test_common/harness/mt19937.c
rename to test_common/harness/mt19937.cpp