瞭解使用Mockito的SharedPreference行爲

Question

我在測試模擬對象時遇到問題，特別是在我自寫的類以及SharedPreferences模擬上。我從我參與的應用程序中提取了一段代碼片段，並將其簡化爲了解正在發生的事情。

我有我的項目中的下列gradle這個設置：

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' 
} 

而且我有這個類在這裏：

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; 
    } 
} 

而且我有這個測試類：

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); 
    } 
} 

現在，我不明白的是，如果我運行testBoolean()一切都按預期工作。但如果我運行testSetRated()兩件事不是按預期工作。

因爲既不when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(false);也不when(preferencesMock.getBoolean(FeedbackManager.RATED, false)).thenReturn(true);雖然他們是相反的失敗。

而且我不明白爲什麼Assert.assertFalse(rated);工作和Assert.assertTrue(rated);失敗。這應該是相反的。

也許我誤解了mock的用法，尤其是SharedPreferences mocks？或者出了什麼問題？

Answer 1

我真的誤解了when(mock.method()).thenReturn(value)的工作原理。它不檢查任何東西。它只是說如果method()被下一次調用，那麼mock對象將返回value。 testSetRated()方法也可以通過查看是否已寫入SharedPreferences進行測試。然後一切按預期工作。