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Testing PhasedBackoffWaitStrategy Timing Behavior in LMAX-Disruptor

This test suite validates the PhasedBackoffWaitStrategy implementation in the LMAX Disruptor library, focusing on sequence change handling with various delay scenarios. The tests verify both lock-based and sleep-based wait strategies under different timing conditions.

Test Coverage Overview

The test suite provides comprehensive coverage of the PhasedBackoffWaitStrategy’s timing behavior.

Key areas tested include:

Immediate sequence changes with no delay
Sequence changes with 1ms, 2ms, and 10ms delays
Both lock-based and sleep-based wait strategy implementations
Edge cases for different timing scenarios

Implementation Analysis

The testing approach employs JUnit 5 framework with systematic delay variations to validate wait strategy behavior. The implementation uses a utility method assertWaitForWithDelayOf to verify timing accuracy across different scenarios.

Technical patterns include:

Parameterized delay testing
Parallel strategy validation
Millisecond-precision timing verification

Technical Details

Testing tools and configuration:

JUnit Jupiter test framework
Custom WaitStrategyTestUtil for assertions
TimeUnit.MILLISECONDS for precise timing
PhasedBackoffWaitStrategy configurations with both lock and sleep mechanisms
Exception handling for timing-related issues

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Systematic test organization with increasing complexity
Parallel validation of different implementation strategies
Consistent test method naming convention
Proper exception handling and timing verification
Clear separation of test cases for different delay scenarios

lmax-exchange/disruptor

src/test/java/com/lmax/disruptor/PhasedBackoffWaitStrategyTest.java

            
/*
 * Copyright 2012 LMAX Ltd.
 *
 * 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 com.lmax.disruptor;

import org.junit.jupiter.api.Test;

import static com.lmax.disruptor.support.WaitStrategyTestUtil.assertWaitForWithDelayOf;
import static java.util.concurrent.TimeUnit.MILLISECONDS;


public class PhasedBackoffWaitStrategyTest
{
    @Test
    public void shouldHandleImmediateSequenceChange() throws Exception
    {
        assertWaitForWithDelayOf(0, PhasedBackoffWaitStrategy.withLock(1, 1, MILLISECONDS));
        assertWaitForWithDelayOf(0, PhasedBackoffWaitStrategy.withSleep(1, 1, MILLISECONDS));
    }

    @Test
    public void shouldHandleSequenceChangeWithOneMillisecondDelay() throws Exception
    {
        assertWaitForWithDelayOf(1, PhasedBackoffWaitStrategy.withLock(1, 1, MILLISECONDS));
        assertWaitForWithDelayOf(1, PhasedBackoffWaitStrategy.withSleep(1, 1, MILLISECONDS));
    }

    @Test
    public void shouldHandleSequenceChangeWithTwoMillisecondDelay() throws Exception
    {
        assertWaitForWithDelayOf(2, PhasedBackoffWaitStrategy.withLock(1, 1, MILLISECONDS));
        assertWaitForWithDelayOf(2, PhasedBackoffWaitStrategy.withSleep(1, 1, MILLISECONDS));
    }

    @Test
    public void shouldHandleSequenceChangeWithTenMillisecondDelay() throws Exception
    {
        assertWaitForWithDelayOf(10, PhasedBackoffWaitStrategy.withLock(1, 1, MILLISECONDS));
        assertWaitForWithDelayOf(10, PhasedBackoffWaitStrategy.withSleep(1, 1, MILLISECONDS));
    }
}