diff --git a/test/sample_unittest.cpp b/test/sample_unittest.cpp
new file mode 100644
index 0000000..2a27279
--- /dev/null
+++ b/test/sample_unittest.cpp
@@ -0,0 +1,6 @@
+#include "sample.h"
+#include <gtest/gtest.h>
+
+TEST(FactorialTest, Zero) {
+    EXPECT_EQ(1, Factorial(0));
+}