diff --git a/tests/test_uncertainty.cpp b/tests/test_uncertainty.cpp
index 6ec71436d7af51ecefdebba1c609192752b2151b..99889d5bd91b30a4db691024e2839e1edb569503 100644
--- a/tests/test_uncertainty.cpp
+++ b/tests/test_uncertainty.cpp
@@ -46,7 +46,7 @@ TEST(UncertaintyTests, TestBootstrapGenerator)
                      {2013, 2013, 2013, 2011},
                      {2013, 2011, 2011, 2011},
                      {2011, 2013, 2013, 2011}};
-#elif EVALHYD_TESTING_OS = LINUX
+#elif EVALHYD_TESTING_OS == LINUX
     sampled_years = {{2011, 2011, 2013, 2011},
                      {2012, 2013, 2013, 2012},
                      {2013, 2011, 2012, 2011},