Testing Cache¶

Deepstaging generates per-entity typed test doubles for [CacheStore] entities. The runtime also provides a generic TestCacheStore for testing custom ICacheStore interactions. No mocking libraries needed.

Generated Test Doubles (CacheStore)¶

Every [Cached] entity gets a Test{Entity}Cache — a typed test double with call recording, seedable state, and Reset().

For this setup:

[TypedId]
public readonly partial struct ProductId;

[Cached]
public partial record Product(ProductId Id, string Name, decimal Price);

[CacheStore]
public static partial class AppCache;

The generator produces TestProductCache : IProductCache alongside the ProductCache implementation.

Call Recording¶

var cache = new TestProductCache();

var id = ProductId.New();
await cache.SetAsync(id, new Product(id, "Widget", 9.99m), TimeSpan.FromMinutes(5));
await cache.GetAsync(id);
await cache.RemoveAsync(id);

await Assert.That(cache.SetCalls).Count().IsEqualTo(1);
await Assert.That(cache.SetCalls[0].Expiration).IsEqualTo(TimeSpan.FromMinutes(5));
await Assert.That(cache.GetCalls).Contains(id);
await Assert.That(cache.RemoveCalls).Contains(id);

Property	Type	Description
`GetCalls`	`IReadOnlyList<ProductId>`	Keys passed to `GetAsync`
`SetCalls`	`IReadOnlyList<(ProductId, Product, TimeSpan?)>`	Calls to `SetAsync` with key, value, expiration
`RemoveCalls`	`IReadOnlyList<ProductId>`	Keys passed to `RemoveAsync`
`InvalidateAllCallCount`	`int`	Number of `InvalidateAllAsync` calls (test-only convenience method)
`Entries`	`IReadOnlyDictionary<ProductId, Product>`	Current cache contents

InvalidateAllAsync is test-only

InvalidateAllAsync is available on TestProductCache as a convenience for clearing test state, but it is not part of the IProductCache interface. Bulk invalidation is a provider-specific operation — see Effects Composition for details.

Seeding¶

Pre-populate cache state without recording calls:

var cache = new TestProductCache();
var id = ProductId.New();
cache.Seed(id, new Product(id, "Widget", 9.99m));

// Seed multiple
cache.Seed(
    (id1, product1),
    (id2, product2)
);

With TestRuntime¶

var cache = new TestProductCache();
cache.Seed(productId, cachedProduct);

var runtime = TestAppRuntime.Create()
    .WithProductCache(cache);

var program =
    from product in AppCache.Products.Get<TestAppRuntime>(productId)
    select product;

var result = await program.RunAsync(runtime);
await Assert.That(result).IsSuccMatching(p => p.IsSome);

Reset¶

cache.Reset(); // Clears entries, calls, and counters

TestCacheStore (ICacheStore Infrastructure)¶

For testing code that interacts directly with ICacheStore (the infrastructure layer), TestCacheStore records every call and tracks cache hits and misses.

var cache = new TestCacheStore();

// Seed a cache value
cache.Seed("user:42", new UserProfile("Alice", "alice@example.com"));

// ... run your handler that reads from cache ...

// Assert cache was consulted
await Assert.That(cache.GetCalls).Contains("user:42");
await Assert.That(cache.Hits).IsEqualTo(1);
await Assert.That(cache.Misses).IsEqualTo(0);

Call Recording¶

Property	Type	Description
`GetCalls`	`IReadOnlyList<string>`	All keys passed to `GetAsync<T>`
`SetCalls`	`IReadOnlyList<CacheSetCall>`	All `SetAsync<T>` calls with key, type, value, and expiration
`RemoveCalls`	`IReadOnlyList<string>`	All keys passed to `RemoveAsync`
`ExistsCalls`	`IReadOnlyList<string>`	All keys passed to `ExistsAsync`
`Hits`	`int`	Number of `GetAsync<T>` calls that returned a value
`Misses`	`int`	Number of `GetAsync<T>` calls that returned `null`

CacheSetCall Record¶

public record CacheSetCall(string Key, Type ValueType, object Value, TimeSpan? Expiration);

Seeding¶

cache.Seed("user:42", new UserProfile("Alice", "alice@example.com"));
cache.Seed("settings", new AppSettings { Theme = "dark" });

Seeded values are stored using JSON serialization, matching real cache behavior.

Asserting Cache Writes¶

var cache = new TestCacheStore();

// ... run handler that caches a result ...

await Assert.That(cache.SetCalls).Count().IsEqualTo(1);
await Assert.That(cache.SetCalls[0].Key).IsEqualTo("user:42");
await Assert.That(cache.SetCalls[0].Expiration).IsEqualTo(TimeSpan.FromMinutes(5));

Reset¶

cache.Reset(); // Clears calls, counters, and seeded values