Android上的Junit测试领域。 无法在未调用Looper.prepare（）的线程内创建处理程序

Question

尝试为领域创建Junit测试，但我似乎在正确设置它方面遇到了一些困难。 我不确定我是否应该异步运行它，我的直觉说不。

在运行时，我得到了越来越流行的错误：

05-26 16:03:32.561 14131-14148/? I/TestRunner: started: aCreateNewPlayer(com.example.gideonsassoon.avariel.RealmTest)
05-26 16:03:32.567 14131-14148/? E/Exception: RealmException Can't create handler inside thread that has not called Looper.prepare()
05-26 16:03:32.568 14131-14148/? W/System.err:     at com.example.gideonsassoon.avariel.database.RealmManager.<init>(RealmManager.java:20)
05-26 16:03:32.568 14131-14148/? W/System.err:     at com.example.gideonsassoon.avariel.RealmTest.aCreateNewPlayer(RealmTest.java:40)
05-26 16:03:32.569 14131-14148/? I/TestRunner: finished: aCreateNewPlayer(com.example.gideonsassoon.avariel.RealmTest)

这是托管和运行所有内容的RealmManager类的代码。

package com.example.gideonsassoon.avariel.database;

import android.app.Activity;
import android.os.Bundle;

import com.example.gideonsassoon.avariel.datamodels.Player;
import com.example.gideonsassoon.avariel.ui.MainFragmentActivity;
import com.facebook.stetho.Stetho;
import com.uphyca.stetho_realm.RealmInspectorModulesProvider;

import io.realm.Realm;
import io.realm.RealmConfiguration;
import io.realm.RealmQuery;
import io.realm.RealmResults;

/**
 * Created by Gideon Sassoon on 16/05/2017.
 */
public class RealmManager extends Activity {

    public static final String TAG = MainFragmentActivity.class.getName();
    private Realm realm;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        //Looper.prepare();
        realm = Realm.getDefaultInstance();
        /**
         * https://realm.io/docs/java/latest/#getting-started
         * http://facebook.github.io/stetho/
         * https://github.com/uPhyca/stetho-realm
         * chrome://inspect/#devices
         */
        Stetho.initializeWithDefaults(this);
        Realm.init(this);
        Stetho.initialize(
                Stetho.newInitializerBuilder(this)
                        .enableDumpapp(Stetho.defaultDumperPluginsProvider(this))
                        .enableWebKitInspector(RealmInspectorModulesProvider.builder(this).build())
                        .build());

        super.onCreate(savedInstanceState);
        Realm.init(this);

        RealmConfiguration config = new RealmConfiguration.Builder().build();
        Realm.setDefaultConfiguration(config);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        realm.close();
    }

    public void savePlayer(Player player) {
        Player player2 = realm.copyToRealm((player));
    }
    public void queryPlayer(String key, String value){
        // https://realm.io/docs/java/latest/#queries
        RealmQuery<Player> query = realm.where(Player.class);
        query.equalTo("playerName","Gideon");
        query.or().equalTo(key, value);
        RealmResults<Player> result1 = query.findAll();
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                Player player  = realm.createObject(Player.class);
                player.setCurrentHP(26);
                player.setAlignment("Lawful Evil");
            }
        });
        //Player player = result1.where().equalTo(key, value).or().equalTo("playerName", "Gideon").findFirst();
    }
}

这是我运行该代码的Junit Test类

package com.example.gideonsassoon.avariel;

import android.support.test.runner.AndroidJUnit4;
import android.util.Log;

import com.example.gideonsassoon.avariel.database.RealmManager;
import com.example.gideonsassoon.avariel.datamodels.Player;

import junit.framework.TestCase;

import org.junit.BeforeClass;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.MethodSorters;

/**
 * Created by Gideon Sassoon on 21/05/2017.
 */
@RunWith(AndroidJUnit4.class)
@FixMethodOrder(MethodSorters.NAME_ASCENDING)

public class RealmTest extends TestCase {

    RealmManager realmManager;
    Player player;
    Player actualPlayerResult;
    String actualStringResult;
    long actualLongResult;

    @BeforeClass
    public static void setup() {
        System.out.println("Before Start /r/n, Welcome to the Doom Room!");
        Log.i("TEST_START", "Before Start /r/n, Welcome to the Doom Room!");
    }

    @Test
    public void aCreateNewPlayer() {
        try {
            realmManager = new RealmManager();
            player = new Player();
            player = player.create(01, "Gideon", "Barlock", "Orc", "Lawful Evil", "Fighter", "A wandering Warrior", 0, 30, 0, null, null, null, null, null, null, null, null, null, 0);
            realmManager.savePlayer(player);
            Log.i("REALM", realmManager.toString());
        } catch (Exception e) {
            // Sep 12, 2013 6:50:17 AM
            Log.e("Exception", "RealmException " + String.valueOf(e.getMessage()));
            e.printStackTrace();
        }
    }

    @Test
    public void bGetPlayer() {
        //actualPlayerResult = Result here;
        realmManager.queryPlayer("playerName", "Gideon");
        Log.i("REALM Test getPlayer", "Our player's name is: " + actualPlayerResult.getName());
    }

    public void cPlacePlayerInApp() {


    }
}

如果您出于任何原因希望看到项目的其余部分。

非常欢迎您在这里这样做:)

Answer 1

出现该错误的原因是因为您通过在以下行中调用构造函数来初始化Activity（ RealmManager ）的子类：

realmManager = new RealmManager(); //won't work because RealmManager is an Activity

虽然Activity，Fragment和Service具有无参数构造函数，但它们被设计为由OS实例化，仅调用构造函数不足以获取功能齐全的实例。

现在，用于编写已测试的单元测试（即，您在Android手机上运行的单元测试）的正确习惯是：

@RunWith(AndroidJUnit4.class)
public class RealmManagerTest { //no need to extend TestCase here!!!!

    public ActivityTestRule<RealmManager> activityRule = new ActivityTestRule<>(RealmManager.class);

    RealmManager realmManager;

    @Before
    public void setUp() throws Exception {
        activityRule.launchActivity(null);
        realmManager = activityRule.getActivity();
    }

ActivityRule将为您正确实例化Activity，将执行从onCreate()到onResume()的回调，并根据需要准备Looper。

请注意，您不再需要扩展TestCase 。 请参阅官方文档 ，以获取有关仪器化单元测试的更多信息。