Add Tier 2 test coverage: SolarIndexWorker, HrrrFetchWorker, IemClient

SolarIndexWorker 36→100% (date-arg clause), HrrrFetchWorker 38→42%
(batch skip, backoff), IemClient 65→74% (fetch_current_asos).

test/microwaveprop/weather/iem_client_test.exs

@@ -223,6 +223,47 @@ defmodule Microwaveprop.Weather.IemClientTest do
     end
   end
 
+  describe "fetch_current_asos/1" do
+    test "returns parsed observations from multiple networks" do
+      Req.Test.stub(IemClient, fn conn ->
+        Req.Test.json(conn, %{
+          "data" => [
+            %{
+              "station" => "KDFW",
+              "lat" => 32.9,
+              "lon" => -97.0,
+              "utc_valid" => "2026-03-28T18:00:00Z",
+              "tmpf" => 75.0,
+              "dwpf" => 55.0,
+              "sknt" => 10,
+              "skyc1" => "CLR",
+              "mslp" => 1013.2,
+              "alti" => 29.92,
+              "phour" => 0.0
+            }
+          ]
+        })
+      end)
+
+      assert {:ok, observations} = IemClient.fetch_current_asos(["TX_ASOS"])
+      assert length(observations) == 1
+      assert hd(observations).station_code == "KDFW"
+      assert hd(observations).temp_f == 75.0
+    end
+
+    test "skips observations with missing core data" do
+      Req.Test.stub(IemClient, fn conn ->
+        Req.Test.json(conn, %{
+          "data" => [
+            %{"station" => "KDFW", "lat" => nil, "lon" => nil, "tmpf" => nil, "dwpf" => nil}
+          ]
+        })
+      end)
+
+      assert {:ok, []} = IemClient.fetch_current_asos(["TX_ASOS"])
+    end
+  end
+
   describe "parse_network_json/1" do
     test "parses station list from network JSON response" do
       json = %{

test/microwaveprop/workers/hrrr_fetch_worker_test.exs

@@ -89,6 +89,34 @@ defmodule Microwaveprop.Workers.HrrrFetchWorkerTest do
     end
   end
 
+  describe "perform/1 batch mode" do
+    test "skips all points when profiles already exist" do
+      Weather.upsert_hrrr_profile(%{
+        valid_time: ~U[2026-03-28 18:00:00Z],
+        lat: 32.90,
+        lon: -97.04,
+        profile: @sample_profile
+      })
+
+      job = %Oban.Job{
+        args: %{
+          "points" => [%{"lat" => 32.90, "lon" => -97.04}],
+          "valid_time" => "2026-03-28T18:00:00Z"
+        }
+      }
+
+      assert :ok = HrrrFetchWorker.perform(job)
+    end
+  end
+
+  describe "backoff/1" do
+    test "returns exponential backoff capped at 6 hours" do
+      assert HrrrFetchWorker.backoff(%Oban.Job{attempt: 1}) == 120
+      assert HrrrFetchWorker.backoff(%Oban.Job{attempt: 2}) == 240
+      assert HrrrFetchWorker.backoff(%Oban.Job{attempt: 10}) <= 21_600
+    end
+  end
+
   describe "permanent_failure?/1" do
     test "cancels on 404 idx" do
       job = %Oban.Job{

test/microwaveprop/workers/solar_index_worker_test.exs

@@ -46,4 +46,26 @@ defmodule Microwaveprop.Workers.SolarIndexWorkerTest do
       assert Repo.aggregate(SolarIndex, :count) == 2
     end
   end
+
+  describe "perform/1 with date arg" do
+    test "fetches and upserts only the matching date" do
+      today = Date.utc_today() |> Date.to_iso8601()
+
+      Req.Test.stub(SolarClient, fn conn ->
+        Req.Test.text(conn, gfz_body_with_recent_dates())
+      end)
+
+      assert :ok = SolarIndexWorker.perform(%Oban.Job{args: %{"date" => today}})
+      assert Repo.aggregate(SolarIndex, :count) == 1
+    end
+
+    test "returns error when HTTP request fails" do
+      Req.Test.stub(SolarClient, fn conn ->
+        Plug.Conn.send_resp(conn, 500, "Internal Server Error")
+      end)
+
+      today = Date.utc_today() |> Date.to_iso8601()
+      assert {:error, "HTTP 500"} = SolarIndexWorker.perform(%Oban.Job{args: %{"date" => today}})
+    end
+  end
 end