使用Mockito了解SharedPreference行为

Question

我在测试mock对象时遇到了问题，尤其是在我自己编写的类以及SharedPreferences mock上。我从我参与的应用程序中提取了一段代码片段，并对其进行了简化，以了解发生了什么

我的项目中有以下等级设置：

apply plugin: 'com.android.application'
android {
    compileSdkVersion 24
    buildToolsVersion "24.0.0"
    defaultConfig {
        applicationId "de.mk_xappo.mockitoexample"
        minSdkVersion 19
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    testCompile 'org.mockito:mockito-core:1.10.19'
    compile 'com.android.support:appcompat-v7:24.1.1'
}

我这里有这样的课：

package de.mk_xappo.mockitoexample;
import android.content.SharedPreferences;

public class FeedbackManager {
    protected static final String RATED = "RATED";
    private final SharedPreferences sharedPreferences;

    public FeedbackManager(SharedPreferences sharedPreferences) {
        this.sharedPreferences = sharedPreferences;
    }
    protected void setRated() {
        sharedPreferences.edit().putBoolean(RATED, true).commit();
    }
    protected boolean getRated() {
        return sharedPreferences.getBoolean(RATED, false);
    }
    protected static boolean getTrue() {
        return true;
    }
    public boolean getFalse() {
        return false;
    }
}

我有一个测试班：

package de.mk_xappo.mockitoexample;
import android.app.Application;
import android.content.SharedPreferences;
import org.junit.Assert;
import org.junit.Test;
import static org.mockito.Matchers.anyBoolean;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyLong;
import static org.mockito.Matchers.anyString;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
public class FeedbackManagerTest {
    private Application applicationMock;
    private SharedPreferences preferencesMock;
    private SharedPreferences.Editor editorMock;
    private FeedbackManager feedbackManager;
    @org.junit.Before
    public void setUp() throws Exception {
        applicationMock = mock(Application.class);
        preferencesMock = mock(SharedPreferences.class);
        when(applicationMock.getSharedPreferences(anyString(), anyInt())).thenReturn(preferencesMock);
        editorMock = mock(SharedPreferences.Editor.class);
        when(editorMock.putBoolean(anyString(), anyBoolean())).thenReturn(editorMock);
        when(editorMock.putLong(anyString(), anyLong())).thenReturn(editorMock);
        when(editorMock.remove(anyString())).thenReturn(editorMock);
        when(preferencesMock.edit()).thenReturn(editorMock);
//        feedbackManager = new FeedbackManager(preferencesMock);
        feedbackManager = mock(FeedbackManager.class);
    }
    @Test
    public void testBoolean() throws Exception {
        Assert.assertTrue(FeedbackManager.getTrue());
        Assert.assertFalse(feedbackManager.getFalse());
    }
    @Test
    public void testSetRated() throws Exception {
        boolean rated = feedbackManager.getRated();
        Assert.assertFalse(rated);
        feedbackManager.setRated();
        rated = feedbackManager.getRated();
        when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(false);
        when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(true);
        Assert.assertFalse(rated);
        Assert.assertTrue(rated);
    }
}

现在，我不明白的是，如果我运行testBoolean()，一切都会按预期工作。但是，如果我运行testSetRated()，两件事就不会像预期的那样工作。

因为when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(false);和when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(true);都没有失败，尽管它们相反。

我不明白为什么Assert.assertFalse(rated);工作而Assert.assertTrue(rated);失败。反之亦然。

也许我误解了mock的用法，尤其是SharedPreferences mock？或者出了什么问题？

Answer 1

我真的误解了when(mock.method()).thenReturn(value)的工作原理。它不检查任何内容。它只是说，如果下次调用method()，mock对象将返回value。testSetRated()方法也可以通过查看是否已经编写了SharedPreferences来进行测试。然后一切都按预期进行。