test: PromEx + Canopy.BulkFetch + Maidenhead.valid? coverage

- PromEx: added dashboards/0 + plugins/0 tests
- Canopy.BulkFetch: 0% -> covers run/4 entry path (all tile fetches fail
  cleanly without network); cache/staging dirs created
- Maidenhead.valid?/1: rejects integer/atom/tuple/list/map inputs
- Canopy.tile_filename/2: S/E hemisphere prefix branches
- ScoreCache.max_entries/0 invariant test

3624 tests, 0 failures.

test/microwaveprop/canopy/bulk_fetch_test.exs

@@ -0,0 +1,52 @@
+defmodule Microwaveprop.Canopy.BulkFetchTest do
+  use ExUnit.Case, async: false
+
+  import ExUnit.CaptureLog
+
+  alias Microwaveprop.Canopy.BulkFetch
+
+  setup do
+    cache_dir = Path.join(System.tmp_dir!(), "canopy_test_#{System.unique_integer([:positive])}")
+    staging_dir = Path.join(System.tmp_dir!(), "canopy_staging_test_#{System.unique_integer([:positive])}")
+
+    on_exit(fn ->
+      File.rm_rf!(cache_dir)
+      File.rm_rf!(staging_dir)
+    end)
+
+    %{cache_dir: cache_dir, staging_dir: staging_dir}
+  end
+
+  describe "run/4" do
+    test "computes degree tiles and reports zero counters when COG fetch fails", %{
+      cache_dir: cache_dir,
+      staging_dir: staging_dir
+    } do
+      # The default ETH cog URL won't be reachable from the test sandbox,
+      # so the per-COG ensure step fails and increments the failed counter
+      # for every degree tile. We just verify run/4 returns a counter map
+      # with the expected keys and never crashes.
+      capture_log(fn ->
+        result = BulkFetch.run(32.5, -97.0, 1, cache_dir: cache_dir, staging_dir: staging_dir)
+        send(self(), result)
+      end)
+
+      assert_received %{
+        downloaded: _,
+        sliced: _,
+        cached: _,
+        failed: _,
+        cache_dir: ^cache_dir
+      }
+    end
+
+    test "creates the cache + staging directories", %{cache_dir: cache_dir, staging_dir: staging_dir} do
+      capture_log(fn ->
+        _ = BulkFetch.run(32.5, -97.0, 1, cache_dir: cache_dir, staging_dir: staging_dir)
+      end)
+
+      assert File.dir?(cache_dir)
+      assert File.dir?(staging_dir)
+    end
+  end
+end

test/microwaveprop/prom_ex_test.exs

@@ -0,0 +1,19 @@
+defmodule Microwaveprop.PromExTest do
+  use ExUnit.Case, async: true
+
+  describe "dashboards/0" do
+    test "returns the configured dashboard list" do
+      dashboards = Microwaveprop.PromEx.dashboards()
+      assert is_list(dashboards)
+      assert {:prom_ex, "application.json"} in dashboards
+    end
+  end
+
+  describe "plugins/0" do
+    test "returns a non-empty plugin list" do
+      plugins = Microwaveprop.PromEx.plugins()
+      assert is_list(plugins)
+      assert plugins != []
+    end
+  end
+end

test/microwaveprop/propagation/score_cache_test.exs

@@ -221,6 +221,13 @@ defmodule Microwaveprop.Propagation.ScoreCacheTest do
     end
   end
 
+  describe "max_entries/0" do
+    test "returns the configured cap as a positive integer" do
+      assert is_integer(ScoreCache.max_entries())
+      assert ScoreCache.max_entries() > 0
+    end
+  end
+
   describe "max-entries eviction" do
     test "caps entries at max_entries, evicting the oldest valid_time" do
       cap = ScoreCache.max_entries()