模拟私有方法

Question

我正在尝试模拟一个在内部调用私有方法的方法。此私有方法使用 classloader.getclass 方法读取文件并填充一个列表，该列表是 class 的静态变量。我尝试了所有可能的方法来模拟这个私有方法，但它似乎不起作用。

class TestLoad {
    private static List <String> myList = new ArrayList <String> ();
    private static final String filename = "/myfile.txt";

    public XYZ generateList(Abc abc) throws Exception {
        populateList();
    }

    private populateList() {
        ClassLoader classLoader = TestLoad.class.getClassLoader();
        File listfile = new File(classLoader.getResource(
        filename).getFile());
        List <String> localList = new ArrayList <String> ();

        try (Scanner scanner = new Scanner(listfile)) {
            while (scanner.hasNextLine()) {
                String text = scanner.nextLine();
                localList.add(text.trim());
            }
            scanner.close();
        } catch (IOException e) {}
        return localList;
    }
}

我正在尝试模拟 populateList() 但控件一直进入该方法。我通过 mockito 和 powermock 尝试了网上几乎所有的选项，但它似乎并不 work.My Junit 如下

Class 开始有@RunWith(PowerMockRunner.class) @PrepareForTest(TestLoad.class) ArrayList testList = new ArrayList(); testList.add("00"); TestLoad 实例 = PowerMock.createPartialMock(TestLoad.class,"populateList"); PowerMock.expectPrivate(实例, "populateList").andReturn(测试列表); PowerMock.replay(实例);

以下日志供参考：

java.lang.IllegalStateException: Failed to transform class with name com.xyz.TestLoad. Reason: java.io.IOException: invalid constant type: 18 at 17 at org.powermock.core.classloader.MockClassLoader.loadMockClass(MockClassLoader.java:266) at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:180) at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:68) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:348) at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:145) at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:40) at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.createTestDelegators(AbstractTestSuiteChunkerImpl.java:244) at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.(JUnit4TestSuiteChunkerImpl.java:61) at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.(AbstractCommonPowerMockRunner.java:32) at org.powermock.modules.junit4.PowerMockRunner.(PowerMockRunner.java:34) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

Answer 1

您的测试代码看起来像是在使用 PowerMock EasyMock。但是您的 post 也被标记为 mockito 和 powermockito。

我正在使用 powermockito 给出以下解决方案。

主要Javaclass:

public class TestLoad {

private static List<String> myList = new ArrayList<String>();
private static final String filename = "/myfile.txt";

public List<String> generateList(Abc abc) throws Exception {

    System.out.println("generateList method is called");
    return populateList();
}

private List<String> populateList() {
    System.out.println("populateList method is called");
    ClassLoader classLoader = TestLoad.class.getClassLoader();
    File listfile = new File(classLoader.getResource(filename).getFile());
    // Read listfile and build localList logic here
    List<String> localList = new ArrayList<String>();

    return localList;
 }
}

测试Javaclass

import java.util.ArrayList;
import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Matchers;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@PrepareForTest(TestLoad.class)
@RunWith(PowerMockRunner.class)
public class TestLoadTest {

@Test
public void testPrivateMethod() throws Exception{

    List<String> testList = new ArrayList<String>();
    testList.add("00");

    TestLoad mockInstance = PowerMockito.spy(new TestLoad());

    PowerMockito.doReturn(testList).when(mockInstance, "populateList");

    List<String> outputList = mockInstance.generateList(new Abc());

    System.out.println("test output:" + outputList);

    PowerMockito.verifyPrivate(mockInstance, Mockito.times(1)).invoke("populateList"); 

}

}

控制台输出：

generateList method is called
test output:[00]

Answer 2

经过大量研究，我找到了解决方案。我们需要在 pom.xml 中添加以下依赖项以防止出现此错误... **

<dependency>
            <groupId>org.javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>3.18.2-GA</version>
        </dependency>

**

模拟私有方法

Mocking a private method

junit

mockito

powermock

easymock

powermockito