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Testing Memory Event Store Rollback and Acknowledgment in Canal

This test suite validates the rollback and acknowledgment functionality of Canal’s memory-based event store implementation, focusing on buffer management and event handling mechanisms.

Test Coverage Overview

The test suite provides comprehensive coverage of memory event store operations with specific focus on rollback and acknowledgment scenarios.

Tests buffer size management and event storage
Validates event position tracking and retrieval
Verifies rollback functionality for partial and complete buffers
Tests acknowledgment (cleanUntil) behavior

Implementation Analysis

The testing approach utilizes JUnit to validate the MemoryEventStoreWithBuffer implementation through systematic test cases.

Tests employ a combination of event generation, buffer manipulation, and state verification to ensure correct behavior of rollback and acknowledgment operations. The implementation uses precise timing controls with sleep() calls to manage event sequencing.

Technical Details

JUnit 4 testing framework
Custom Event and Position model classes
MemoryEventStoreWithBuffer as primary test subject
Buffer size of 16 events for testing
CanalEventUtils for position management

Best Practices Demonstrated

The test suite demonstrates several testing best practices including:

Isolated test methods for distinct functionality
Systematic setup and teardown of test resources
Comprehensive assertion coverage
Clear test case organization
Proper error handling and resource cleanup

alibaba/canal

store/src/test/java/com/alibaba/otter/canal/store/memory/buffer/MemoryEventStoreRollbackAndAckTest.java

            
package com.alibaba.otter.canal.store.memory.buffer;

import java.util.ArrayList;
import java.util.List;

import org.junit.Assert;
import org.junit.Test;

import com.alibaba.otter.canal.protocol.position.Position;
import com.alibaba.otter.canal.store.helper.CanalEventUtils;
import com.alibaba.otter.canal.store.memory.MemoryEventStoreWithBuffer;
import com.alibaba.otter.canal.store.model.Event;
import com.alibaba.otter.canal.store.model.Events;

/**
 * 测试下rollback / ack的操作
 * 
 * @author jianghang 2012-6-19 下午09:49:28
 * @version 1.0.0
 */
public class MemoryEventStoreRollbackAndAckTest extends MemoryEventStoreBase {

    @Test
    public void testRollback() {
        int bufferSize = 16;
        MemoryEventStoreWithBuffer eventStore = new MemoryEventStoreWithBuffer();
        eventStore.setBufferSize(bufferSize);
        eventStore.start();

        for (int i = 0; i < bufferSize / 2; i++) {
            boolean result = eventStore.tryPut(buildEvent("1", 1L, 1L + i));
            sleep(100L);
            Assert.assertTrue(result);
        }

        sleep(50L);
        Position first = eventStore.getFirstPosition();
        Position lastest = eventStore.getLatestPosition();
        Assert.assertEquals(first, CanalEventUtils.createPosition(buildEvent("1", 1L, 1L)));
        Assert.assertEquals(lastest, CanalEventUtils.createPosition(buildEvent("1", 1L, 1L + bufferSize / 2 - 1)));

        System.out.println("start get");
        Events<Event> entrys1 = eventStore.tryGet(first, bufferSize);
        System.out.println("first get size : " + entrys1.getEvents().size());

        eventStore.rollback();

        entrys1 = eventStore.tryGet(first, bufferSize);
        System.out.println("after rollback get size : " + entrys1.getEvents().size());
        Assert.assertTrue(entrys1.getEvents().size() == bufferSize / 2);

        // 继续造数据
        for (int i = bufferSize / 2; i < bufferSize; i++) {
            boolean result = eventStore.tryPut(buildEvent("1", 1L, 1L + i));
            sleep(100L);
            Assert.assertTrue(result);
        }

        Events<Event> entrys2 = eventStore.tryGet(entrys1.getPositionRange().getEnd(), bufferSize);
        System.out.println("second get size : " + entrys2.getEvents().size());

        eventStore.rollback();

        entrys2 = eventStore.tryGet(entrys1.getPositionRange().getEnd(), bufferSize);
        System.out.println("after rollback get size : " + entrys2.getEvents().size());
        Assert.assertTrue(entrys2.getEvents().size() == bufferSize);

        first = eventStore.getFirstPosition();
        lastest = eventStore.getLatestPosition();
        List<Event> entrys = new ArrayList<>(entrys2.getEvents());
        Assert.assertTrue(entrys.size() == bufferSize);
        Assert.assertEquals(first, entrys2.getPositionRange().getStart());
        Assert.assertEquals(lastest, entrys2.getPositionRange().getEnd());

        Assert.assertEquals(first, CanalEventUtils.createPosition(entrys.get(0)));
        Assert.assertEquals(lastest, CanalEventUtils.createPosition(entrys.get(bufferSize - 1)));
        eventStore.stop();
    }

    @Test
    public void testAck() {
        int bufferSize = 16;
        MemoryEventStoreWithBuffer eventStore = new MemoryEventStoreWithBuffer();
        eventStore.setBufferSize(bufferSize);
        eventStore.start();

        for (int i = 0; i < bufferSize / 2; i++) {
            boolean result = eventStore.tryPut(buildEvent("1", 1L, 1L + i));
            sleep(100L);
            Assert.assertTrue(result);
        }

        sleep(50L);
        Position first = eventStore.getFirstPosition();
        Position lastest = eventStore.getLatestPosition();
        Assert.assertEquals(first, CanalEventUtils.createPosition(buildEvent("1", 1L, 1L)));
        Assert.assertEquals(lastest, CanalEventUtils.createPosition(buildEvent("1", 1L, 1L + bufferSize / 2 - 1)));

        System.out.println("start get");
        Events<Event> entrys1 = eventStore.tryGet(first, bufferSize);
        System.out.println("first get size : " + entrys1.getEvents().size());

        eventStore.cleanUntil(entrys1.getPositionRange().getEnd());
        sleep(50L);

        // 继续造数据
        for (int i = bufferSize / 2; i < bufferSize; i++) {
            boolean result = eventStore.tryPut(buildEvent("1", 1L, 1L + i));
            sleep(100L);
            Assert.assertTrue(result);
        }

        Events<Event> entrys2 = eventStore.tryGet(entrys1.getPositionRange().getEnd(), bufferSize);
        System.out.println("second get size : " + entrys2.getEvents().size());

        eventStore.rollback();

        entrys2 = eventStore.tryGet(entrys1.getPositionRange().getEnd(), bufferSize);
        System.out.println("after rollback get size : " + entrys2.getEvents().size());

        first = eventStore.getFirstPosition();
        lastest = eventStore.getLatestPosition();
        List<Event> entrys = new ArrayList<>(entrys2.getEvents());
        // because doGet() contains the logic about whether include first event , so not to compare
        //Assert.assertEquals(first, entrys2.getPositionRange().getStart());
        Assert.assertEquals(lastest, entrys2.getPositionRange().getEnd());

        // the reason same as above
        //Assert.assertEquals(first, CanalEventUtils.createPosition(entrys.get(0)));
        Assert.assertEquals(lastest, CanalEventUtils.createPosition(entrys.get(entrys.size() - 1)));

        // 全部ack掉
        eventStore.cleanUntil(entrys2.getPositionRange().getEnd());

        // 最后就拿不到数据
        Events<Event> entrys3 = eventStore.tryGet(entrys1.getPositionRange().getEnd(), bufferSize);
        System.out.println("third get size : " + entrys3.getEvents().size());
        Assert.assertEquals(0, entrys3.getEvents().size());

        eventStore.stop();
    }

}