diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 4cef254..15f80dd 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -161,4 +161,10 @@ void test_arcSine(void) {
     // Add more test cases for different inputs and expected outputs
 }
 
+void test_arcCosine(void) {
+    float result = arcCosine(0.5);
+    TEST_ASSERT_EQUAL_FLOAT(1.047198, result);
+    // Add more test cases for different inputs and expected outputs
+}
+
 #endif
\ No newline at end of file