# `AshCache.Testing`
[🔗](https://github.com/Undeadlol1/ash_cache/blob/v0.1.0/lib/ash_cache/testing.ex#L1)

Lets a test see the cache events its own code caused, even when many
tests run at the same time (`async: true`).

AshCache announces cache hits, misses (of reads, generic actions and
calculations) and invalidations with `:telemetry`
(see `AshCache`). Telemetry handlers are global, so a plain handler would
also catch events from other tests running in parallel. Call
`capture_events/0` instead:

    setup do
      AshCache.Testing.capture_events()
    end

    test "lookup is cached" do
      MyApp.Shop.get_product_by_sku!("A1")
      MyApp.Shop.get_product_by_sku!("A1")
      assert_received {:ash_cache, :hit, %{action: :get_by_sku}}
    end

Each event arrives in the test's mailbox as
`{:ash_cache, kind, metadata}`. `kind` is `:hit`, `:miss` or `:invalidate`,
and `metadata` is the telemetry metadata described in `AshCache`.

Only events caused by the test are delivered: those from the test process
itself and from Tasks it started. Events from any other process, such as a
GenServer started elsewhere, are dropped. The handler is removed
automatically when the test ends.

# `capture_events`

```elixir
@spec capture_events() :: :ok
```

Starts delivering cache events to the calling test process.

Call it from the test process, in `setup` or in the test itself.

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*Consult [api-reference.md](api-reference.md) for complete listing*