Cast timestamp to utc_datetime in testing queries

Timestamps with a timezone are now cast to `:utc_datetime` via a
changeset before running `Oban.Testing` queries. This fixes a regression
introduced in f8e5785.

Closes #977

lib/oban/testing.ex

@@ -610,13 +610,12 @@ defmodule Oban.Testing do
   defp conditions({key, val}, query) when key in @timestamp_fields do
     {time, delta} =
       case val do
-        {time, delta: delta} ->
-          {time, delta}
-
-        time ->
-          {time, 1}
+        {time, delta: delta} -> {time, delta}
+        time -> {time, 1}
       end
 
+    {:ok, time} = Ecto.Type.cast(:utc_datetime, time)
+
     begin = DateTime.add(time, -delta, :second)
     until = DateTime.add(time, +delta, :second)
 

test/oban/testing_test.exs

@@ -264,6 +264,7 @@ defmodule Oban.TestingTest do
       insert!(%{}, worker: Pong, scheduled_at: seconds_from_now(60))
 
       assert_enqueued worker: Ping, state: "available", scheduled_at: DateTime.utc_now()
+      assert_enqueued worker: Ping, scheduled_at: DateTime.now!("America/Chicago")
       assert_enqueued worker: Pong, scheduled_at: seconds_from_now(60)
       assert_enqueued worker: Pong, scheduled_at: {seconds_from_now(69), delta: 10}
     end