diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 0f0b22c..39eb3d5 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -37,4 +37,10 @@ void test_absolute(void) {
     TEST_ASSERT_EQUAL_FLOAT(5.0, result);
 }
 
+void test_logarithm(void) {
+    float result = logarithm(100.0);
+    TEST_ASSERT_FLOAT_WITHIN(0.000001, 2.0, result);
+    // Add more test cases for different inputs and expected outputs
+}
+
 #endif
\ No newline at end of file