使用Power Mockito模拟方法调用-org.powermock.api.mockito.ClassNotPreparedException [英] Mocking method calls using power mockito - org.powermock.api.mockito.ClassNotPreparedException

问题描述

我有一个图像加载器类，我需要在其中测试一些静态方法.由于Mockito不支持静态方法，因此我切换到Power Mockito.但是我正在测试的静态方法有一个方法调用

I have an image loader class and i need to test some static methods in it. Since Mockito does not support static methods i switched to Power Mockito. But the static method i am testing has a method call

 Base64.encodeToString(byteArray, Base64.DEFAULT);

要对此进行模拟，我将使用下面的 mockStatic 方法和@PrepareForTest批注.

To mock this i am using mockStatic method as below with @PrepareForTest annotation.

 PowerMockito.mockStatic(Base64.class);

但是Android Studio仍在返回我，但仍然返回以下错误.

But Android studio is returning me still returning me an error as below.

org.powermock.api.mockito.ClassNotPreparedException:该类 android.util.Base64未准备好进行测试.要准备这个课程，请添加 类到"@PrepareForTest"注释.

org.powermock.api.mockito.ClassNotPreparedException: The class android.util.Base64 not prepared for test. To prepare this class, add class to the '@PrepareForTest' annotation.

下面是我的完整代码.

要测试的代码:

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import android.widget.ImageView;

  public static String convertBitmapToBase64(Bitmap imageBitmap, boolean withCompression) {
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    imageBitmap.compress(Bitmap.CompressFormat.PNG, 120, byteArrayOutputStream);
    byte[] byteArray = byteArrayOutputStream.toByteArray();
    return Base64.encodeToString(byteArray, Base64.DEFAULT);
}

测试类代码

import android.graphics.Bitmap;
import android.util.Base64;
import org.junit.Before;
import org.junit.runner.RunWith;
import org.mockito.MockitoAnnotations;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.testng.annotations.Test;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Base64.class})
public class ImageLoaderTest  {
@Test
   public void testConvertBitmap(){
    byte[] array = new byte[20];
    PowerMockito.mockStatic(Base64.class);
    PowerMockito.when(Base64.encodeToString(array, Base64.DEFAULT)).thenReturn("asdfghjkl");
    Bitmap mockedBitmap= PowerMockito.mock(Bitmap.class);
    String output = ImageLoaderUtils.convertBitmapToBase64(mockedBitmap);
    assert (!output.isEmpty());
}

}

等级依赖性

testCompile 'junit:junit:4.12'
testCompile 'org.powermock:powermock:1.6.5'
testCompile 'org.powermock:powermock-module-junit4:1.6.5'
testCompile 'org.powermock:powermock-api-mockito:1.6.5'

推荐答案

您无法回答的简短内容.来自常见问题解答:

Short answer you can't. Here from the FAQ:

Mockito有哪些局限性

What are the limitations of Mockito

• 无法模拟最终课程
• 无法模拟静态方法
• 无法模拟最终方法-执行它们的实际行为没有任何异常. Mockito无法警告您有关模拟最终方法的信息，因此 保持警惕.

• Cannot mock final classes
• Cannot mock static methods
• Cannot mock final methods - their real behavior is executed without any exception. Mockito cannot warn you about mocking final methods so be vigilant.

有关此限制的更多信息:

Further information about this limitation:

我可以模拟静态方法吗?

Can I mock static methods?

不. Mockito更喜欢面向对象和依赖项注入 静态，难以理解的程序代码改变.如果你 处理可怕的旧代码，您可以使用JMockit或Powermock进行模拟 静态方法.

No. Mockito prefers object orientation and dependency injection over static, procedural code that is hard to understand & change. If you deal with scary legacy code you can use JMockit or Powermock to mock static methods.

如果要使用PowerMock，请尝试如下操作:

If you want to use PowerMock try like this:

@RunWith(PowerMockRunner.class)
@PrepareForTest( { Base64.class })
public class YourTestCase {
    @Test
    public void testStatic() {
        mockStatic(Base64.class);
        when(Base64.encodeToString(argument)).thenReturn("expected result");
    }
}

在 Mockito 2中，现在可以模拟最终的类了和最终方法.这是一个选择加入的选项.您需要使用以下内容创建文件src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker:

In Mockito 2 it's now possible to mock final Class and final Method. It's an opt-in option. You need to create the file src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker with the following content:

mock-maker-inline

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