Files
Musify/backend/Tests/Musify.Infrastructure.Tests/Services/SingleFlightCacheTests.cs
T

81 lines
2.6 KiB
C#

using ErrorOr;
using Microsoft.Extensions.Caching.Memory;
using Musify.Infrastructure.Services;
using Xunit;
namespace Musify.Infrastructure.Tests.Services;
public sealed class SingleFlightCacheTests
{
private static SingleFlightCache CreateCache() => new(new MemoryCache(new MemoryCacheOptions()));
[Fact]
public async Task GetOrCreateAsync_SecondCallWithinDuration_ReturnsCachedValueWithoutCallingFactory()
{
var cache = CreateCache();
var calls = 0;
Task<ErrorOr<int>> Factory() { calls++; return Task.FromResult<ErrorOr<int>>(calls); }
var first = await cache.GetOrCreateAsync("key", TimeSpan.FromMinutes(1), Factory);
var second = await cache.GetOrCreateAsync("key", TimeSpan.FromMinutes(1), Factory);
Assert.Equal(1, first.Value);
Assert.Equal(1, second.Value);
Assert.Equal(1, calls);
}
[Fact]
public async Task GetOrCreateAsync_ConcurrentCallsForTheSameKey_CollapseIntoASingleFactoryCall()
{
var cache = CreateCache();
var calls = 0;
var gate = new TaskCompletionSource();
async Task<ErrorOr<int>> Factory()
{
Interlocked.Increment(ref calls);
await gate.Task;
return 7;
}
var first = cache.GetOrCreateAsync("concurrent-key", TimeSpan.FromMinutes(1), Factory);
var second = cache.GetOrCreateAsync("concurrent-key", TimeSpan.FromMinutes(1), Factory);
gate.SetResult();
var results = await Task.WhenAll(first, second);
Assert.Equal(1, calls);
Assert.All(results, result => Assert.Equal(7, result.Value));
}
[Fact]
public async Task GetOrCreateAsync_FactoryReturnsError_DoesNotCacheIt()
{
var cache = CreateCache();
var calls = 0;
Task<ErrorOr<int>> Factory()
{
calls++;
return Task.FromResult<ErrorOr<int>>(Error.Failure(description: "boom"));
}
await cache.GetOrCreateAsync("error-key", TimeSpan.FromMinutes(1), Factory);
await cache.GetOrCreateAsync("error-key", TimeSpan.FromMinutes(1), Factory);
Assert.Equal(2, calls);
}
[Fact]
public async Task GetOrCreateAsync_NonPositiveDuration_AlwaysCallsTheFactory()
{
var cache = CreateCache();
var calls = 0;
Task<ErrorOr<int>> Factory() { calls++; return Task.FromResult<ErrorOr<int>>(calls); }
await cache.GetOrCreateAsync("no-cache-key", TimeSpan.Zero, Factory);
await cache.GetOrCreateAsync("no-cache-key", TimeSpan.Zero, Factory);
Assert.Equal(2, calls);
}
}