使用原始参数模拟方法时 Mockito 中的 NullPointerException

2022-01-14 00:00:00 unit-testing mockito java

我花了最后一点时间拔头发试图在我的测试中找到问题，并最终发现它与模拟一个采用原始参数的方法有关.这是一个演示问题的示例测试:

I've spent the last little while pulling out my hair trying to find the problem in my test, and eventually figured out it has to do with mocking a method that takes primitive arguments. Here's a sample test that demos the problem:

import static org.mockito.Matchers.any;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import org.junit.Test;

public class MockitoTest {
    public static interface Foo {
        public Object causeProblems(long arg);
    }

    @Test
    public void testFoo() {
        Foo foo = mock(Foo.class);
        foo.causeProblems(123);
        verify(foo, times(1)).causeProblems(any());
    }
}

运行此测试时(我使用的是 Mockito 1.10 和 Java8)，由于某种原因，我的堆栈跟踪在 verify 行上显示了 NPE:

When running this test (I'm using Mockito 1.10 and Java8), and for some reason my stack trace is showing an NPE on the verify line:

java.lang.NullPointerException
    at com.amazon.jetstream.executor.worker.invoke.MockitoTest.testFoo(MockitoTest.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
....

我认为我的堆栈跟踪的一部分被抑制了(?)深入研究它，如果我在 Eclipse 中运行它并检查"该行，我可以从中获得更多信息，这告诉我简单:

I think part of my stack trace is being suppressed (?) Digging into it a bit further, I can get slightly more info out of it if I run it in Eclipse and "inspect" the line, which tells me simply: 

java.lang.NullPointerException at longValue()

问题:

  1. 有谁知道如何解决这个错误?
  2. 如果你能重现这个，你能从你的堆栈跟踪中获得更多信息吗?

推荐答案

你应该匹配 long 不匹配任何对象的匹配器:

You should matcher that matches long not any object:

verify(foo, times(1)).causeProblems(anyLong());

我检查了它是否正常运行.

I checked that it runs correctly.

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