模拟Java枚举以添加一个值来测试失败案例 [英] Mocking Java enum to add a value to test fail case

问题描述

我有一个或多个这样的开关：

I have an enum switch more or less like this:

public static enum MyEnum {A, B}

public int foo(MyEnum value) {
    switch(value) {
        case(A): return calculateSomething();
        case(B): return calculateSomethingElse();
    }
    throw new IllegalArgumentException("Do not know how to handle " + value);
}

我想让测试覆盖所有的行，但因为代码预期会处理所有的可能性，所以我不能在交换机中提供没有相应的case语句的值。

and I'd like to have all the lines covered by the tests, but as the code is expected to deal with all possibilities, I cannot supply a value without its corresponding case statement in the switch.

扩展枚举以添加额外的值不是可能的，只是嘲笑equals方法返回 false 将无法正常工作，因为生成的字节码使用窗帘后面的跳转表去适当的情况...所以我以为可能有一些黑魔法可以用PowerMock或某些东西来实现。

Extending the enum to add an extra value is not possible, and just mocking the equals method to return false won't work either because the bytecode generated uses a jump table behind the curtains to go to the proper case... So I've thought that maybe some black magic could be achieved with PowerMock or something.

谢谢！

strong>编辑：

edit:

由于我拥有枚举，我以为我可以添加一个方法到值，从而避免交换机的问题;但是我仍然会留下这个问题，因为它仍然是有趣的。

As I own the enumeration, I've thought that I could just add a method to the values and thus avoid the switch issue completely; but I'm leaving the question as it's still interesting.

推荐答案

Java专家通讯有一个问题（ http://www.javaspecialists.eu/archive/Issue161.html ），试图解决这种问题。它涉及各种反思魔法和SUN内部类的使用。我承认我没有完全阅读，但也许这对你有兴趣？

There's an issue of the Java Specialists newsletter (http://www.javaspecialists.eu/archive/Issue161.html) that tried to tackle this kind of problem. It involves all kinds of reflection magic and usage of SUN internal classes. I admit that I haven't read it completely, but maybe it's of interest to you?

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