Added operation handler unittest for operation input

test/test_operationHandler.c

@@ -0,0 +1,28 @@
+#include "../src/operationHandler.h"
+#include "unity.h"
+
+void setUp(void) {
+    // set stuff up here
+}
+
+void tearDown(void) {
+    // clean stuff up here
+}
+
+void test_operationHandler_truereturnvaluewithvalidinput(void) {
+    int expectedResult = 1;
+    int result1 = checkOperationInput(1);
+    int result2 = checkOperationInput(2);
+    int result3 = checkOperationInput(3);
+    int result4 = checkOperationInput(4);
+    TEST_ASSERT_EQUAL_INT(expectedResult, result1);
+    TEST_ASSERT_EQUAL_INT(expectedResult, result2);
+    TEST_ASSERT_EQUAL_INT(expectedResult, result3);
+    TEST_ASSERT_EQUAL_INT(expectedResult, result4);
+}
+
+void test_operationHandler_falsereturnvaluewithinvalidinput(void) {
+    int expectedResult = 0;
+    int result = checkOperationInput(8);
+    TEST_ASSERT_EQUAL_INT(expectedResult, result);
+}