diff --git a/test/test_trigonometricFunctions.c b/test/test_trigonometricFunctions.c
index 45e1328..f21eb02 100644
--- a/test/test_trigonometricFunctions.c
+++ b/test/test_trigonometricFunctions.c
@@ -20,4 +20,10 @@ void test_trigonometricFunctions_trigonometricFunctionsofcos(void) {
     double *result;
     result = calculate_cos_double(45);
     TEST_ASSERT_DOUBLE_WITHIN(0.1, expectedResult, *result);
+}
+void test_trigonometricFunctions_trigonometricFunctionsoftan(void) {
+    double expectedResult = 1.61977519 ;
+    double *result;
+    result = calculate_tan_double(45);
+    TEST_ASSERT_DOUBLE_WITHIN(0.1, expectedResult, *result);
 }
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