Added test for operation handler extracting method

test/test_operationHandler.c

@@ -46,4 +46,11 @@ void test_operationHandler_extractingFirstNumber(void) {
     char str[] = {'4', '8', ' ', '5', '\0'};
     int result = extractFirstNumber(str);
     TEST_ASSERT_EQUAL_INT(expectedResult, result);
-}
+}
+
+void test_operationHandler_removefirstnumberfromoriginalstring(void) {
+    char expected[] = {'5', '\0'};
+    char str[] = {'4', '8', ' ', '5', '\0'};
+    extractFirstNumber(str);
+    TEST_ASSERT_EQUAL_STRING(expected, str);
+}