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using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Jellyfin.Database.Implementations.Locking;
using Microsoft.Data.Sqlite;
using Microsoft.Extensions.Logging.Abstractions;
using Polly.Utilities;
using Xunit;
namespace Jellyfin.Server.Implementations.Tests.Locking;
/// <summary>
/// The retries of <see cref="OptimisticLockBehavior"/> when the database stays locked. Polly's clock records the
/// waits instead of sleeping through them, and the save hooks never use the context, so none is created.
/// </summary>
public sealed class OptimisticLockBehaviorTests : IDisposable
{
private static readonly TimeSpan[] _sleepDurations =
[
TimeSpan.FromMilliseconds(50),
TimeSpan.FromMilliseconds(50),
TimeSpan.FromMilliseconds(50),
TimeSpan.FromMilliseconds(50),
TimeSpan.FromMilliseconds(250),
TimeSpan.FromMilliseconds(250),
TimeSpan.FromMilliseconds(250),
TimeSpan.FromMilliseconds(150),
TimeSpan.FromMilliseconds(150),
TimeSpan.FromMilliseconds(150),
TimeSpan.FromMilliseconds(500),
TimeSpan.FromMilliseconds(150),
TimeSpan.FromMilliseconds(500),
TimeSpan.FromMilliseconds(150),
TimeSpan.FromSeconds(3)
];
private readonly List<TimeSpan> _waits = [];
private readonly OptimisticLockBehavior _behavior = new(NullLogger<OptimisticLockBehavior>.Instance);
public OptimisticLockBehaviorTests()
{
SystemClock.Sleep = (wait, _) => _waits.Add(wait);
SystemClock.SleepAsync = (wait, _) =>
{
_waits.Add(wait);
return Task.CompletedTask;
};
}
public void Dispose()
{
SystemClock.Reset();
}
[Fact]
public void OnSaveChanges_DatabaseLockedBriefly_WaitsTheConfiguredDurationsInOrder()
{
var attempts = 0;
_behavior.OnSaveChanges(null!, () =>
{
if (++attempts <= 5)
{
throw DatabaseLocked();
}
});
Assert.Equal(6, attempts);
AssertWaits(5);
}
[Fact]
public void OnSaveChanges_DatabaseStaysLocked_ThrowsTheDatabaseErrorAfterTheLastRetry()
{
var attempts = 0;
Assert.Throws<SqliteException>(() => _behavior.OnSaveChanges(null!, () =>
{
attempts++;
throw DatabaseLocked();
}));
Assert.Equal(_sleepDurations.Length + 1, attempts);
AssertWaits(_sleepDurations.Length);
}
[Fact]
public async Task OnSaveChangesAsync_DatabaseStaysLocked_ThrowsTheDatabaseErrorAfterTheLastRetry()
{
var attempts = 0;
await Assert.ThrowsAsync<SqliteException>(() => _behavior.OnSaveChangesAsync(null!, () =>
{
attempts++;
throw DatabaseLocked();
}));
Assert.Equal(_sleepDurations.Length + 1, attempts);
AssertWaits(_sleepDurations.Length);
}
private static SqliteException DatabaseLocked() => new("SQLite Error 5: 'database is locked'.", 5);
private void AssertWaits(int retries)
{
Assert.Equal(retries, _waits.Count);
for (var i = 0; i < retries; i++)
{
// The configured duration plus a jitter of less than half of it.
Assert.InRange(_waits[i], _sleepDurations[i], _sleepDurations[i] * 1.5);
}
}
}
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