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Testing Android Event Handling Implementation in greenrobot/EventBus

This test suite implements Android-specific functionality for EventBus event handling and posting mechanisms. It provides a foundation for testing event dispatching across different Android threads while ensuring proper Looper and Handler implementations.

Test Coverage Overview

The test suite covers Android-specific event posting mechanisms and thread handling in EventBus.

Tests event posting through Android’s main thread Looper
Validates Handler implementation for event dispatching
Ensures proper thread separation between test and main threads
Covers initialization of Android-specific EventBus components

Implementation Analysis

The testing approach utilizes AndroidJUnit4 runner for Android-specific test execution. It implements an abstract base class pattern that extends AbstractEventBusTest while adding Android-specific functionality.

Key implementation features include:

Custom EventPostHandler extending Android Handler
Main thread Looper integration
Thread safety validation between test and main threads

Technical Details

Testing infrastructure includes:

AndroidJUnit4 test runner
Android Support Test libraries
Android Handler and Looper mechanisms
SuppressLint annotations for Handler implementation
JUnit Assert utilities

Best Practices Demonstrated

The test implementation showcases several Android testing best practices.

Proper separation of concerns between Android and base EventBus testing
Thread-safe event posting mechanisms
Clean inheritance structure for test organization
Proper Android component lifecycle management
Efficient message handling patterns

greenrobot/eventbus

EventBusTest/src/org/greenrobot/eventbus/AbstractAndroidEventBusTest.java

            
/*
 * Copyright (C) 2012-2016 Markus Junginger, greenrobot (http://greenrobot.org)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.greenrobot.eventbus;

import android.annotation.SuppressLint;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.test.runner.AndroidJUnit4;

import org.junit.Before;
import org.junit.runner.RunWith;


import static org.junit.Assert.assertFalse;

/**
 * @author Markus Junginger, greenrobot
 */
@RunWith(AndroidJUnit4.class)
public abstract class AbstractAndroidEventBusTest extends AbstractEventBusTest {
    private EventPostHandler mainPoster;

    public AbstractAndroidEventBusTest() {
        this(false);
    }

    public AbstractAndroidEventBusTest(boolean collectEventsReceived) {
        super(collectEventsReceived);
    }

    @Before
    public void setUpAndroid() throws Exception {
        mainPoster = new EventPostHandler(Looper.getMainLooper());
        assertFalse(Looper.getMainLooper().getThread().equals(Thread.currentThread()));
    }

    protected void postInMainThread(Object event) {
        mainPoster.post(event);
    }

    @SuppressLint("HandlerLeak")
    class EventPostHandler extends Handler {
        public EventPostHandler(Looper looper) {
            super(looper);
        }

        @Override
        public void handleMessage(Message msg) {
            eventBus.post(msg.obj);
        }

        void post(Object event) {
            sendMessage(obtainMessage(0, event));
        }

    }

}