无法使用Mkdirs（）调用Java void方法模拟创建目录

Question

在尝试运行以下代码的测试时。下面我会详细介绍一些错误。

当我尝试运行测试时，我观察到它在我的代码投掷 IllegalArgumentException thrws thrws中的mkdirs（）调用时观察到。

myclass.java

package com.javaeasily.demos.junit;

import java.util.ArrayList;

public class MyClass {
    private final NodeHelper nodeHelper;
    private static final ArrayList<String> ACTIVE_SERVICES_POST_RECONFIGURE = new ArrayList<>();

    // Only allow construction if number is greater than one
    MyClass() {
        ACTIVE_SERVICES_POST_RECONFIGURE.add("my-node-" + NodeUtils.getMyNode());
        nodeHelper = new NodeHelper();
    }

    public void reconfigureNode() {
        if (ACTIVE_SERVICES_POST_RECONFIGURE.isEmpty()) {
            return;
        }
        try {
            nodeHelper.createStagingDir();
        } catch (Exception e) {
            throw new RuntimeException("Cannot reconfigure node");
        }
    }
}

nodeutils.java

package com.javaeasily.demos.junit;


import org.apache.commons.lang3.StringUtils;

public class NodeUtils {
    private static final String HOSTNAME_PREFIX = "my-node-";

    public static String hostnameToNode(String hostname) {
        if (!hostname.startsWith(HOSTNAME_PREFIX)) {
            throw new IllegalArgumentException(hostname + " is not recognized hostname");
        }
        return StringUtils.removeStart(hostname, HOSTNAME_PREFIX);
    }

    public static String getHostname() {
        return System.getenv("HOSTNAME");
    }

    public static String getMyNode() {
        return hostnameToNode(getHostname());
    }
}

nodehelper.java

package com.javaeasily.demos.junit;

import java.io.File;

public class NodeHelper {
    private static final String STAGING_DIR = "/staging/";

    public void createStagingDir() {
        File stagingDir = new File(STAGING_DIR);
        if (!stagingDir.exists() && !stagingDir.mkdirs()) {
            throw new IllegalArgumentException("Could not create staging dir");
        }
    }
}

myclasstest.java

package com.javaeasily.demos.junit;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.MockedStatic;
import org.mockito.Mockito;
import org.mockito.junit.jupiter.MockitoExtension;

@ExtendWith(MockitoExtension.class)
public class MyClassTest {
    private MyClass myclass;

    @BeforeEach
    public void SetUp() {
        try (MockedStatic<NodeUtils> nodeUtilsMockedStatic = Mockito.mockStatic(NodeUtils.class);) {
            nodeUtilsMockedStatic.when(NodeUtils::getMyNode).thenReturn("foo");
            myclass = new MyClass();
        }
    }

    @Test
    public void testReconfigureNode() {
        myclass.reconfigureNode();
    }
}

当我尝试进行测试时，我会关注错误：

java.lang.RuntimeException: Cannot reconfigure node

    at com.javaeasily.demos.junit.MyClass.reconfigureNode(MyClass.java:22)

邮政调试，我看到了：

java.lang.IllegalArgumentException: Could not create staging dir

有人在乎启发我关于我做错了什么吗？

Answer 1

要模拟NodeHelper您不应在myClass中创建它，而应通过构造函数从外部注入它。即，

MyClass(Nodehelper nodeHelper) {
    ACTIVE_SERVICES_POST_RECONFIGURE.add("my-node-" + NodeUtils.getMyNode());
    this.nodeHelper = nodeHelper;
}

这使您可以在测试中创建模拟的nodehelper，将其传递到myClass并将所需的行为设置为期望。