测试（junit）switch 语句中的默认情况？

Question

I need to know how to test the default case in a switch statement with junit. I can't change the code itself and I'm trying for 100% coverage but I don't know how to test my default. Helps?

public Hello helloSwitch() {
        Hello hi = Hello.A;
        switch (this) {
        case A:
            hi = Hello.B;
            break;
        case B:
            hi = Hello.C;
            break;
        case C:
            hi = Hello.A;
            break;
        default:
            hi = Hello.A;
            break;
        }

I had to modify the code a fair bit so sorry that it looks silly. I just need to know how to write a junit to test the default, I've tested everything else.

I can't change this code.

Edit: changed

Edit: This code isn't important I jut need to know how to write the unit test for the default

Edit: I can't change, the code itself, I'm only writing the tests. I need 100% coverage though.

Answer 1

Let me assume that 'hallo' is a variable set somewhere outside the given method. Let me further assume that the Enum type currently only allows values present in the switch statement. In this case you can use "null" to trigger the default case. In this case the default statement is unreachable and should not be there at all. While there might be ways to still "test" this - meaning to execute the code running a test - this would not add any benefit. If you have more enum constants available than pick any covered by the default case.

As some already have mentioned:

• dead code cannot and should not be tested but removed.
• 100% test coverage sounds nice but usually is not a realistic or sensible goal
• in my opinion test shouldn't even know about the code in a method but test the method as a black box.

Answer 2

visit this link can help you : [JUnit is a standardized framework for testing Java units (that is, Java classes). JUnit can be automated to take the some of the work out of testing.

Imagine you've created an enum type with three values: GREEN, YELLOW, and RED. Listing 1 contains the code: http://www.dummies.com/programming/java/using-junit ] 1