diff --git a/test/conversionOfNumbers/test_conversionOfNumbers.c b/test/conversionOfNumbers/test_conversionOfNumbers.c
index 897bcb9..5b11535 100644
--- a/test/conversionOfNumbers/test_conversionOfNumbers.c
+++ b/test/conversionOfNumbers/test_conversionOfNumbers.c
@@ -162,6 +162,18 @@ void test_hexStringLengthOfInput255is2(){
     //act
     result = hexStrLen(255);
 
+    //assert
+    TEST_ASSERT_EQUAL_INT(expected, result);
+}
+
+void test_hexStringLengthOfInput0is1(){
+    //arrange
+    int result;
+    int expected = 1;
+
+    //act
+    result = hexStrLen(0);
+
     //assert
     TEST_ASSERT_EQUAL_INT(expected, result);
 }
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