Added test for operation handler extracting method

test/test_operationHandler.c

@@ -47,3 +47,10 @@ void test_operationHandler_extractingFirstNumber(void) {
     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);
+}