java - Mockito 不会在 super 方法上触发 doReturn

Question

我正在测试一些遗留代码并尝试模拟父类(super class)中的某些行为。奇怪的是，mockito 不会触发并返回我期望的值，在某些情况下，它甚至在 doReturn 行上抛出 NullpointerException 。相关代码如下:

要测试的类

package mypackage;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;

public abstract class MyClass extends PushbackInputStream
{


  public MyClass(InputStream in)
  {
    super(in, 20);
  }

  protected final void checkIaikPkcs7() throws IOException
  {
    byte[] buffer = getInstantiatedByteArray(20);
    if (super.read(buffer, 0, buffer.length) != buffer.length)
    {
      throw new IOException("unable to read needed data");
    }
    ...
  }

  protected byte[] getInstantiatedByteArray(int size)
  {
    return new byte[size];
  }
}

带有测试的类(class)

public class MyClassTest
{
  private MyClass spy;
  private InputStream inputStreamMock;

  @Before
  public void setUp() throws Exception
  {
    this.inputStreamMock = mock(InputStream.class);
    this.spy = spy(new MyObjectClassExtendingMyClass(inputStreamMock));
  }

  @After
  public void tearDown() throws Exception
  {
    this.spy = null;
    this.inputStreamMock = null;
  }


  @Test
  public void testCheckIaikPkcs7() throws IOException
  {
    //assure that read is called with exactly the same parameters in mock and implementation
    byte[] byteArray = new byte[20];
    doReturn(byteArray).when(this.spy).getInstantiatedByteArray(20);

    // want 20 returned, but the Test returns 0 (propably not recognizing this line)
    doReturn(20).when(this.spy).read(byteArray, 0, byteArray.length);
    this.spy.checkIaikPkcs7();
  }

}

或者，我将 doReturn(20).... 替换为

    doReturn(20).when(this.spy).read(any(), any(), any());

但随后我得到一个 NullPointerException。我看不出哪里出了问题，非常感谢您的帮助。

到目前为止谢谢你

Answer 1

如果您不需要重写read，只需使用this.read而不是super.read，您的代码就可以工作。

参见Mockito How to mock only the call of a method of the superclass

NullPointerException 的第二个问题:对于接受原始 int

的参数，您需要使用 anyInt()，而不是 any()