在为 Espresso 测试创建活动之前更改共享偏好

Question

我正在尝试为登录页面创建 Espresso 测试，但我遇到了一个问题，即一旦涉及成功登录的测试运行后，任何后续测试现在都处于错误活动中，并且需要重新运行登录测试完全重新启动虚拟设备以清除共享首选项（这是因为 loginactivity 检查所述首选项以查看是否成功登录并跳到主应用程序页面）。

我的问题是，一旦创建了 ActivityScenarioRule，更改共享首选项已经为时已晚，因为活动已经更改为主页。这是我的代码：

package com.androidapp.zitgenius;


import static androidx.test.espresso.Espresso.onView;

import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;
import android.view.View;

import androidx.test.espresso.intent.Intents;
import androidx.test.ext.junit.rules.ActivityScenarioRule;
import androidx.test.ext.junit.runners.AndroidJUnit4;

import org.junit.After;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import static androidx.test.espresso.action.ViewActions.click;
import static androidx.test.espresso.action.ViewActions.closeSoftKeyboard;
import static androidx.test.espresso.action.ViewActions.typeText;
import static androidx.test.espresso.assertion.ViewAssertions.matches;
import static androidx.test.espresso.intent.Intents.intended;
import static androidx.test.espresso.intent.matcher.IntentMatchers.hasComponent;
import static androidx.test.espresso.matcher.ViewMatchers.withId;
import static androidx.test.espresso.matcher.ViewMatchers.withText;
import static androidx.test.platform.app.InstrumentationRegistry.getInstrumentation;

/**
 * Instrumented test of Login Activity, which will execute on an Android device.
 *
 * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
 */
@RunWith(AndroidJUnit4.class)

public class LoginActivityTest{
    public final String INCORRECT_USERNAME = "this isn't a real username";
    public final String INCORRECT_PASSWORD = "this isn't a real password";
    public final String CORRECT_USERNAME = "test2@l.com";
    public final String CORRECT_PASSWORD = "123";
    private static final String SHARE_PREF_NAME ="login_ref" ;
    private static final String KEY_USER_ID ="id" ;

    public void setSharedPrefs(){
        SharedPreferences sharedPreferences = getInstrumentation().getContext().getSharedPreferences(SHARE_PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit() ;
        editor.putInt(KEY_USER_ID, -1) ;
        editor.apply();  //this will prevent automatic logins from disrupting tests
        Log.i("TESTING","Setting up shared prefs");

    }
    @Rule
    public ActivityScenarioRule<LoginActivity> activityScenarioRule
            = new ActivityScenarioRule<>(LoginActivity.class);
    private View decorView;

    @Before
    public void setUp() {
        Intents.init();
        setSharedPrefs();
        activityScenarioRule
                = new ActivityScenarioRule<>(LoginActivity.class);
    }
    @Test
    public void inputLoginJustUsername() {
        SharedPreferences sharedPreferences = getInstrumentation().getContext().getSharedPreferences(SHARE_PREF_NAME, Context.MODE_PRIVATE);

        Log.i("TESTING",String.valueOf(sharedPreferences.getInt(KEY_USER_ID, -1)));
        //Type text and then hit Login Button
        onView(withId(R.id.editText_username_input)).perform(typeText(CORRECT_USERNAME), closeSoftKeyboard());
        onView(withId(R.id.button_login)).perform(click());

        // Confirm inputted text remains
        onView(withId(R.id.editText_username_input)).check(matches(withText(CORRECT_USERNAME)));

        //TODO: Confirm Toast error message
    }
    @Test
    public void inputLoginJustPassword() {
        //Type text and then hit Login Button
        onView(withId(R.id.editText_password_input)).perform(typeText(CORRECT_PASSWORD), closeSoftKeyboard());
        onView(withId(R.id.button_login)).perform(click());

        // Confirm inputted text remains
        onView(withId(R.id.editText_password_input)).check(matches(withText(CORRECT_PASSWORD)));

        //TODO: Confirm Toast error message
    }
    @Test
    public void inputLoginIncorrectCredentials() {
        //Type text and then hit Login Button
        onView(withId(R.id.editText_username_input)).perform(typeText(INCORRECT_USERNAME), closeSoftKeyboard());
        onView(withId(R.id.editText_password_input)).perform(typeText(INCORRECT_PASSWORD), closeSoftKeyboard());
        onView(withId(R.id.button_login)).perform(click());

        // Confirm inputted text remains
        onView(withId(R.id.editText_username_input)).check(matches(withText(INCORRECT_USERNAME)));
        onView(withId(R.id.editText_password_input)).check(matches(withText(INCORRECT_PASSWORD)));

        //TODO: Confirm Toast error message
    }
    @Test
    public void inputLoginCorrectCredentials() {
        Log.i("TESTING", "Starting correct cred test");
        int totalMillisToWait = 3000;
        int pollEveryMillis = 300;
        //Type text and then hit Login Button
        onView(withId(R.id.editText_username_input)).perform(typeText(CORRECT_USERNAME), closeSoftKeyboard());
        onView(withId(R.id.editText_password_input)).perform(typeText(CORRECT_PASSWORD), closeSoftKeyboard());
        onView(withId(R.id.button_login)).perform(click());
        //Wait for response
        for(int i = 0; i < totalMillisToWait/pollEveryMillis; i++){
            try {
                Thread.sleep((long)pollEveryMillis);
            } catch(InterruptedException e) {
                System.out.println("got interrupted!");
            }
        }
        // Confirm transition to NavBarActivity
        Log.i("TESTING", "Checking intents");
        intended(hasComponent(BottomNavigationActivity.class.getName()));

    }
    @Test
    public void switchToSignupActivity() {
        //Hit button to switch to signup
        onView(withId(R.id.button_switch_signup)).perform(click());

        // Confirm transition to Signup Activity
        intended(hasComponent(SignupActivity.class.getName()));
    }

    @After
    public void tearDown() throws Exception {
        Intents.release();
    }

    }

Answer 1

我相信您的问题在于使用ActivityScenarioRule，我认为它会在您声明它后立即为您启动一个活动，我总是发现它有问题，因此不要使用该规则。

我认为你可以尝试两件事：

1 - 将您的偏好设置逻辑提取到规则中并确保首先调用它：

// Here SharedPreferencesRule is a custom rule based on your "setSharedPrefs" function
// I'll leave that as an exercise to the reader
@Rule
public RuleChain rules = RuleChain.outer(new SharedPreferencesRule())
                                  .around(new ActivityScenarioRule<>(LoginActivity.class))

并更新Before中的逻辑：

@Before
public void setUp() {
    Intents.init();
    // setSharedPrefs(); // This would no longer exist, done by the rule
    //  activityScenarioRule // Delete this
    //        = new ActivityScenarioRule<>(LoginActivity.class);
}

2 - 将 ActivityScenarioRule 替换为手动管理的场景

只需手动启动和控制场景，可能在您的设置中进行类似行为：

// Remove this rule
// @Rule
// public ActivityScenarioRule<LoginActivity> activityScenarioRule
//      = new ActivityScenarioRule<>(LoginActivity.class);

private ActivityScenario<LoginActivity> scenario = null;

private View decorView;

@Before
public void setUp() {
    Intents.init();

    setSharedPrefs(); // Set prefs before launching activity

    scenario = ActivityScenario.launch(LoginActivity.class);
}

@After
public void tearDown() throws Exception {
    Intents.release();
    scenario.close();
}