test: expand coverage on ionosphere + space_weather contexts

6 additional characterization tests for empty-list upsert paths, station
filter isolation on latest_observation/1, multi-band xray coexistence,
and newest-across-time/bands latest_* helpers.

test/microwaveprop/ionosphere/ionosphere_test.exs

@@ -79,6 +79,28 @@ defmodule Microwaveprop.IonosphereTest do
     test "returns nil when no observations exist for the station" do
       assert Ionosphere.latest_observation("MHJ45") == nil
     end
+
+    test "filters by station_code (another station's newer row does not leak through)" do
+      mhj_old =
+        @valid_attrs
+        |> Map.delete(:station_code)
+        |> Map.put(:valid_time, ~U[2026-04-15 18:00:00Z])
+        |> Map.put(:fo_es_mhz, 4.0)
+
+      al_newer =
+        @valid_attrs
+        |> Map.delete(:station_code)
+        |> Map.put(:valid_time, ~U[2026-04-15 23:00:00Z])
+        |> Map.put(:fo_es_mhz, 11.0)
+
+      {:ok, _} = Ionosphere.upsert_observations("MHJ45", [mhj_old])
+      {:ok, _} = Ionosphere.upsert_observations("AL945", [al_newer])
+
+      row = Ionosphere.latest_observation("MHJ45")
+      assert row.station_code == "MHJ45"
+      assert row.valid_time == ~U[2026-04-15 18:00:00Z]
+      assert row.fo_es_mhz == 4.0
+    end
   end
 
   describe "nearest_foes/3" do

test/microwaveprop/space_weather/space_weather_test.exs

@@ -54,6 +54,11 @@ defmodule Microwaveprop.SpaceWeatherTest do
       assert [stored] = Repo.all(SolarFluxObservation)
       assert stored.flux_sfu == 120.0
     end
+
+    test "empty list is a no-op returning {:ok, 0}" do
+      assert {:ok, 0} = SpaceWeather.upsert_solar_flux([])
+      assert Repo.aggregate(SolarFluxObservation, :count, :id) == 0
+    end
   end
 
   describe "upsert_xray/1" do
@@ -79,6 +84,31 @@ defmodule Microwaveprop.SpaceWeatherTest do
       [stored] = Repo.all(SolarXrayObservation)
       assert stored.flux_wm2 == 4.0e-7
     end
+
+    test "rows with same valid_time but different energy_band coexist" do
+      rows = [
+        %{
+          valid_time: ~U[2026-04-14 19:49:00Z],
+          satellite: 18,
+          flux_wm2: 3.5e-7,
+          energy_band: "0.1-0.8nm"
+        },
+        %{
+          valid_time: ~U[2026-04-14 19:49:00Z],
+          satellite: 18,
+          flux_wm2: 1.2e-8,
+          energy_band: "0.05-0.4nm"
+        }
+      ]
+
+      assert {:ok, 2} = SpaceWeather.upsert_xray(rows)
+      assert Repo.aggregate(SolarXrayObservation, :count, :id) == 2
+    end
+
+    test "empty list is a no-op returning {:ok, 0}" do
+      assert {:ok, 0} = SpaceWeather.upsert_xray([])
+      assert Repo.aggregate(SolarXrayObservation, :count, :id) == 0
+    end
   end
 
   describe "latest_kp/0" do
@@ -120,5 +150,46 @@ defmodule Microwaveprop.SpaceWeatherTest do
       assert %SolarFluxObservation{flux_sfu: 112.0} = SpaceWeather.latest_f107()
       assert %SolarXrayObservation{flux_wm2: 1.0e-7} = SpaceWeather.latest_xray()
     end
+
+    test "latest_f107/0 picks newest across multiple observations" do
+      {:ok, _} =
+        SpaceWeather.upsert_solar_flux([
+          %{valid_time: ~U[2026-04-14 20:00:00Z], frequency_mhz: 2800, flux_sfu: 100.0},
+          %{valid_time: ~U[2026-04-15 20:00:00Z], frequency_mhz: 2800, flux_sfu: 115.0},
+          %{valid_time: ~U[2026-04-13 20:00:00Z], frequency_mhz: 2800, flux_sfu: 90.0}
+        ])
+
+      row = SpaceWeather.latest_f107()
+      assert row.valid_time == ~U[2026-04-15 20:00:00Z]
+      assert row.flux_sfu == 115.0
+    end
+
+    test "latest_xray/0 picks newest across multiple energy bands" do
+      {:ok, _} =
+        SpaceWeather.upsert_xray([
+          %{
+            valid_time: ~U[2026-04-15 17:00:00Z],
+            satellite: 18,
+            flux_wm2: 1.0e-7,
+            energy_band: "0.1-0.8nm"
+          },
+          %{
+            valid_time: ~U[2026-04-15 18:00:00Z],
+            satellite: 18,
+            flux_wm2: 2.0e-7,
+            energy_band: "0.05-0.4nm"
+          },
+          %{
+            valid_time: ~U[2026-04-15 17:30:00Z],
+            satellite: 18,
+            flux_wm2: 3.0e-7,
+            energy_band: "0.1-0.8nm"
+          }
+        ])
+
+      row = SpaceWeather.latest_xray()
+      assert row.valid_time == ~U[2026-04-15 18:00:00Z]
+      assert row.flux_wm2 == 2.0e-7
+    end
   end
 end