Fix BackfillEnqueueWorker test timeouts and credo length warnings

The three BackfillEnqueueWorkerTest cases were timing out because the
default types list includes :era5, which cascades through inline Oban
into Era5Client.poll_and_download where Process.sleep blocks for the
full 60s test timeout. Era5Client uses bare Req.get with no plug hook,
so it can't be stubbed via Req.Test the way the other clients are. Pass
explicit non-ERA5 types in the three affected cases — ERA5 has its own
coverage and these tests don't assert anything era5-specific.

Also replace two `length(results) > 0` checks in asos_nudge_test with
`results != []` to silence credo warnings.

test/microwaveprop/propagation/asos_nudge_test.exs

@@ -159,7 +159,7 @@ defmodule Microwaveprop.Propagation.AsosNudgeTest do
 
       results = AsosNudge.compute([obs], @valid_time, [hrrr])
 
-      assert length(results) > 0
+      assert results != []
 
       for result <- results do
         assert result.lat == 32.0
@@ -189,7 +189,7 @@ defmodule Microwaveprop.Propagation.AsosNudgeTest do
 
       results = AsosNudge.compute([], @valid_time, [far_cell], rain_grid)
 
-      assert length(results) > 0
+      assert results != []
       lat_lons = results |> Enum.map(&{&1.lat, &1.lon}) |> Enum.uniq()
       assert {40.0, -85.0} in lat_lons
     end

test/microwaveprop/workers/backfill_enqueue_worker_test.exs

@@ -56,11 +56,19 @@ defmodule Microwaveprop.Workers.BackfillEnqueueWorkerTest do
     :ok
   end
 
+  # ERA5 goes through Copernicus CDS API which is async (submit → poll → download)
+  # and has no Req.Test plug hook, so inline Oban would block on Process.sleep.
+  # These tests exercise the non-ERA5 enrichment path; ERA5 has its own coverage.
+  @non_era5_types ["hrrr", "weather", "terrain", "iemre"]
+
   describe "perform/1" do
     test "enqueues enrichment jobs for pending contacts" do
       create_contact()
 
-      assert :ok = BackfillEnqueueWorker.perform(%Oban.Job{args: %{"limit" => 10}})
+      assert :ok =
+               BackfillEnqueueWorker.perform(%Oban.Job{
+                 args: %{"limit" => 10, "types" => @non_era5_types}
+               })
     end
 
     test "does not enqueue for already-complete contacts" do
@@ -75,7 +83,10 @@ defmodule Microwaveprop.Workers.BackfillEnqueueWorkerTest do
       })
       |> Repo.update!()
 
-      assert :ok = BackfillEnqueueWorker.perform(%Oban.Job{args: %{"limit" => 10}})
+      assert :ok =
+               BackfillEnqueueWorker.perform(%Oban.Job{
+                 args: %{"limit" => 10, "types" => @non_era5_types}
+               })
     end
 
     test "respects limit parameter" do
@@ -84,7 +95,10 @@ defmodule Microwaveprop.Workers.BackfillEnqueueWorkerTest do
         create_contact(%{qso_timestamp: ts})
       end
 
-      assert :ok = BackfillEnqueueWorker.perform(%Oban.Job{args: %{"limit" => 2}})
+      assert :ok =
+               BackfillEnqueueWorker.perform(%Oban.Job{
+                 args: %{"limit" => 2, "types" => @non_era5_types}
+               })
     end
 
     test "broadcasts enqueue_complete with count" do
@@ -92,7 +106,10 @@ defmodule Microwaveprop.Workers.BackfillEnqueueWorkerTest do
 
       create_contact()
 
-      assert :ok = BackfillEnqueueWorker.perform(%Oban.Job{args: %{"limit" => 10}})
+      assert :ok =
+               BackfillEnqueueWorker.perform(%Oban.Job{
+                 args: %{"limit" => 10, "types" => @non_era5_types}
+               })
 
       assert_receive {:enqueue_complete, 1}
     end