refactoring: change variable names in test_displayMenuCalculator

tests/test_displayMenuCalculator.c

@@ -14,10 +14,10 @@ void tearDown(void)
 
 void test_displayMenuCalculator(void)
 {
-    int e, a;
-    e = 1;
-    a = check();
-    TEST_ASSERT_EQUAL_INT(e, a);
+    int expected, actual;                   //Arrange
+    expected = 1;
+    actual = check();                       //Act
+    TEST_ASSERT_EQUAL_INT(expected, actual);//Assert
 }