如何测试Job类执行期间锁的有效性？求设计优化建议

现有Job类核心实现 #

为确保Job仅执行一次，我给Job类引入了自定义Locking机制，核心方法StartAsync代码如下：

public async Task StartAsync(CancellationToken cancellationToken)
{
    if (this.@lock.IsLocked())
    {
        return;
    }

    this.@lock.Lock();

    await this.ExecuteAsync(new JobExecutionContext(cancellationToken))
        .ConfigureAwait(false);

    this.@lock.Unlock();
}

已编写的测试用例 #

我遵循测试外部可观测行为而非实现细节的原则，使用AutoFixture编写了以下测试（已省略样板代码）：

[Theory(DisplayName = "Starting a `Job` (when the lock is locked), does NOT execute it.")]
[AutoDomainData]
public async Task StartingWithLockedLockDoesLockNotExecuteIt([Frozen] Mock<ILock> lockMock,
    [Frozen] Mock<Job> jobMock)
{
    // VALIDATION.
    ILock @lock = lockMock?.Object ?? throw new ArgumentNullException(nameof(lockMock));
    Job job = jobMock?.Object ?? throw new ArgumentNullException(nameof(jobMock));

    // MOCK SETUP.
    _ = lockMock.Setup(x => x.IsLocked())
        .Returns(true);

    // ACT.
    await job.StartAsync(new CancellationToken())
        .ConfigureAwait(false);

    // ASSERT.
    jobMock.Verify(job => job.ExecuteAsync(It.IsAny<IExecutionContext>()), Times.Never);
}

[Theory(DisplayName = "Starting a `Job` (when the lock is NOT locked), does lock the lock.")]
[AutoDomainData]
public async Task StartingWithNotLockedLockDoesExecuteIt([Frozen] Mock<ILock> lockMock,
    [Frozen] Mock<Job> jobMock)
{
    // VALIDATION.
    ILock @lock = lockMock?.Object ?? throw new ArgumentNullException(nameof(lockMock));
    Job job = jobMock?.Object ?? throw new ArgumentNullException(nameof(jobMock));

    // MOCK SETUP.
    _ = lockMock.Setup(x => x.IsLocked())
        .Returns(false);

    // ACT.
    await job.StartAsync(new CancellationToken())
        .ConfigureAwait(false);

    // ASSERT.
    jobMock.Verify(job => job.ExecuteAsync(It.IsAny<IExecutionContext>()), Times.Once);
}

已覆盖的测试场景 #

• 当锁处于锁定状态时，Job不会执行
• 当锁未锁定时，Job会执行

待解决的问题 #

目前缺少一个关键测试场景：确保Job执行期间，锁始终处于激活状态。同时我感觉现有设计可能存在优化空间，但不确定具体方向，希望得到以下帮助：

1. 如何正确测试"Job执行期间锁始终激活"这个场景？
2. 针对当前的锁机制设计，有哪些优化建议？

内容的提问来源于stack exchange，提问作者Complexity