java - 将自定义消息添加到 JUnit4 样式异常测试

Question

我有以下测试:

@Test(expected=ArithmeticException.class) 
   public void divideByZero() {
   int n = 2 / 1;
}

如图所示here .

我想添加一条消息，如果此测试失败，将打印该消息。

例如，如果我正在进行断言测试，我会执行以下操作来添加一条消息:

@Test public void assertFail(){
    Assert.fail("This is the error message I want printed.");
    Assert.assertEquals(true, false);
}

第二个例子应该打印出“This is the error message I want printed.”。如何设置第一个示例消息文本？

Answer 1

也许 @Rule 注释应该有所帮助。在你的单元测试类中添加这样的东西:

import org.junit.Rule;
import org.junit.rules.MethodRule;
import org.junit.runners.model.Statement;
import org.junit.runners.model.FrameworkMethod;
import org.junit.internal.runners.model.MultipleFailureException;
...
@Rule
public MethodRule failureHandler = new MethodRule()
{
    @Override
    public Statement apply(final Statement base, FrameworkMethod method, Object target)
    {
        return new Statement()
        {
            @Override
            public void evaluate() throws Throwable
            {
                List<Throwable> listErrors = new ArrayList<Throwable>();
                try
                {
                    // Let's execute whatever test runner likes to do
                    base.evaluate();
                }
                catch (Throwable testException)
                {
                    // Your test has failed. Store the test case exception
                    listErrors.add(testException);                        
                    // Now do whatever you need, like adding your message,
                    // capture a screenshot, etc.,
                    // but make sure no exception gets out of there -
                    // catch it and add to listErrors
                }
                if (listErrors.isEmpty())
                {
                    return;
                }
                if (listErrors.size() == 1)
                {
                    throw listErrors.get(0);
                }
                throw new MultipleFailureException(listErrors);
            }
        };
    }
};

与其在 listErrors 中收集所有异常，不如考虑将 testException 与您的异常和附加消息一起包装起来，然后将其抛出。