diff --git a/test/conversionOfNumbers/test_conversionOfNumbers.c b/test/conversionOfNumbers/test_conversionOfNumbers.c
index a823000..fe9441a 100644
--- a/test/conversionOfNumbers/test_conversionOfNumbers.c
+++ b/test/conversionOfNumbers/test_conversionOfNumbers.c
@@ -50,4 +50,16 @@ void test_convert10ToBinaryStr1010(){
 
     //assert
     TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+void test_binaryStringLengthOfInputNegative10is5(){
+    //arrange
+    int result;
+    int expected = 5;
+
+    //act
+    result = binaryStrLen(-10);
+
+    //assert
+    TEST_ASSERT_EQUAL_INT(expected, result);
 }
\ No newline at end of file