diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 15f80dd..fc41a9b 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -167,4 +167,9 @@ void test_arcCosine(void) {
     // Add more test cases for different inputs and expected outputs
 }
 
+void test_arcTangent(void) {
+    float result = arcTangent(1.0);
+    TEST_ASSERT_EQUAL_FLOAT(0.785398, result);
+    // Add more test cases for different inputs and expected outputs
+}
 #endif
\ No newline at end of file