ash-project · skanderm · Jul 4, 2025
diff --git a/test/reactor/executor/compensation_test.exs b/test/reactor/executor/compensation_test.exs
@@ -0,0 +1,83 @@
+defmodule Reactor.Executor.CompensationTest do
+  use ExUnit.Case, async: true
+
+  alias Reactor.Error.Invalid.RunStepError
+
+  defmodule EventMiddleware do
+    use Reactor.Middleware
+
+    @moduledoc false
+    def event(event, _step, context) do
+      Agent.update(context.event_agent, fn events ->
+        [append_elem(event, context.current_try) | events]
+      end)
+
+      :ok
+    end
+
+    defp append_elem(event, elem) when is_tuple(event) do
+      event
+      |> Tuple.to_list()
+      |> Kernel.++([elem])
+      |> List.to_tuple()
+    end
+
+    defp append_elem(event, _), do: event
+  end
+
+  def run(reactor, args, opts \\ []) do
+    {:ok, pid} = Agent.start_link(fn -> [] end)
+
+    reactor.reactor()
+    |> Reactor.Builder.ensure_middleware!(EventMiddleware)
+    |> Reactor.run(args, %{event_agent: pid}, opts)
+
+    Agent.get(pid, fn events -> Enum.reverse(events) end)
+  end
+
+  defmodule CompensateReactor do
+    @moduledoc false
+    use Reactor
+
+    input :compensation_result
+
+    step :fail do
+      argument :compensation_result, input(:compensation_result)
+      max_retries 3
+
+      run fn _, %{current_try: current_try} ->
+        if current_try > 1 do
+          {:ok, :done}
+        else
+          {:error, :fail}
+        end
+      end
+
+      compensate fn _, arguments, _ ->
+        arguments.compensation_result
+      end
+    end
+  end
+
+  test "increments current_try" do
+    assert [
+             {:run_start, _, 0},
+             {:run_error, %RunStepError{error: :fail}, 0},
+             {:compensate_start, %RunStepError{error: :fail}, 0},
+             :compensate_retry,
+             # Current behavior (current_try does not immediately increment).
+             # Uncomment to make the test pass:
+            #  {:run_start, _, 0},
+            #  {:run_error, %RunStepError{error: :fail}, 0},
+            #  {:compensate_start, %RunStepError{error: :fail}, 0},
+            #  :compensate_retry,
+             {:run_start, _, 1},
+             {:run_error, %RunStepError{error: :fail}, 1},
+             {:compensate_start, %RunStepError{error: :fail}, 1},
+             :compensate_retry,
+             {:run_start, _, 2},
+             {:run_complete, :done, 2}
+           ] =
+             run(CompensateReactor, %{compensation_result: :retry}, async?: false)
+  end
+end