如何使用powerMock在同一个类中模拟静态和非静态方法？

Question

我有一个简单的案例来说明一个更复杂的案例（哦，Legacy Code，我爱你吗，吟游诗人应该以你的名义唱出美妙的歌曲）。

一组类的图片如下：

• 实用程序类：

package org.osef.test;

public final class A {

    private static A instance;
    public static String status;

    private A() {
        initPaths();
    }

    public static A getInstance(){
            if(instance==null){
                instance = new A();
            }
            return instance;
    }

    private void initPaths() {
        A.status = "I have been in the method !";
    }
    public String doStuff() {
        return "stuff done ...";
    }
}

• 调用它的类

package org.osef.test;

public class B {

    public String doBdo() {
        A instance = A.getInstance();
        return instance.doStuff();
    }
}

• 测试这堆废话的班级……咳咳……非常困难的“逻辑”。

包 org.osef.test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

import org.easymock.EasyMock;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.powermock.reflect.Whitebox;

@RunWith(PowerMockRunner.class)
@PrepareForTest({ A.class })
public class BTest {

    @Before
    public void setUp() {
        PowerMock.replace(PowerMock.method(A.class, "getInstance")).with(PowerMock.method(BTest.class, "giveOutInstance"));

        A a = A.getInstance();

        EasyMock.expect(a.doStuff()).andReturn("lol");
        EasyMock.replay(a);
    }

    @Test
    public void testDoBdo() {

        B b = new B();
        assertEquals("lol", b.doBdo());
        assertNull(A.status);
    }

    public static A giveOutInstance(){
        return Whitebox.newInstance(A.class);
    }
}

• 另一种方法已经如下：

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

import org.easymock.EasyMock;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.powermock.reflect.Whitebox;

@RunWith(PowerMockRunner.class)
@PrepareForTest({ A.class })
public class BTest {

    @Before
    public void setUp() {
        PowerMock.replace(PowerMock.method(A.class, "getInstance")).with(PowerMock.method(BTest.class, "giveOutInstance"));

        A a = A.getInstance();

        EasyMock.expect(a.doStuff()).andReturn("lol");
        EasyMock.replay(a);
    }

    @Test
    public void testDoBdo() {

        B b = new B();
        assertEquals("lol", b.doBdo());
        assertNull(A.status);
    }

    public static A giveOutInstance(){
        return Whitebox.newInstance(A.class);
    }
}

但在所有情况下，我都得到：

java.lang.IllegalStateException: 在 org.easymock.EasyMock.getControlForLastCall(EasyMock.java:560) at org.easymock.EasyMock.expect(EasyMock.java:538) at org.osef.test 上没有对模拟可用的最后一次调用。 BTest.setUp(BTest.java:25) ...

• 我只需要测试最后的 A 类。
• 我需要避免它的构造函数逻辑（在我对 doStuff" 方法的测试中是可怕的和无关紧要的）。
• 我必须测试那个 doStuff。

知道如何有效地做我想做的事吗？

Answer 1

我认为你的问题是你没有重播这些类，你只是在每个测试中重播 A 的模拟实例。

PowerMock.replayAll()是你的朋友吗？它将强制您期望的类处于重播模式，然后可以通过调用静态方法返回您的模拟实例。

这是我为您的示例制作的示例测试：

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import org.easymock.EasyMock;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(A.class)
public class BTest{

    @Test
    public void thatCallingClassMakesExpectedCalls() {
        final A mockA = PowerMock.createMock(A.class);
        EasyMock.expect(mockA.doStuff()).andReturn("lol").anyTimes();

        PowerMock.mockStatic(A.class);
        EasyMock.expect(A.getInstance()).andReturn(mockA).anyTimes();

        PowerMock.replayAll(mockA);

        final B callingClass = new B();
        final String doBdo = callingClass.doBdo();
        assertThat(doBdo, is("lol"));

        EasyMock.verify(mockA);
        PowerMock.verifyAll();
    }
}