ML-181: harden assets endpoints

test/music_library/assets/transform_test.exs

@@ -2,4 +2,52 @@ defmodule MusicLibrary.Assets.TransformTest do
   use ExUnit.Case, async: true
 
   doctest MusicLibrary.Assets.Transform
+
+  alias MusicLibrary.Assets.Transform
+
+  defp make_payload(params) do
+    params |> JSON.encode!() |> Base.url_encode64(padding: false)
+  end
+
+  describe "decode/1 width validation" do
+    test "rejects string width" do
+      payload = make_payload(%{hash: "abc", width: "300"})
+      assert {:error, :invalid_payload} = Transform.decode(payload)
+    end
+
+    test "rejects negative width" do
+      payload = make_payload(%{hash: "abc", width: -1})
+      assert {:error, :invalid_payload} = Transform.decode(payload)
+    end
+
+    test "rejects zero width" do
+      payload = make_payload(%{hash: "abc", width: 0})
+      assert {:error, :invalid_payload} = Transform.decode(payload)
+    end
+
+    test "rejects float width" do
+      payload = make_payload(%{hash: "abc", width: 300.5})
+      assert {:error, :invalid_payload} = Transform.decode(payload)
+    end
+
+    test "rejects very large width" do
+      payload = make_payload(%{hash: "abc", width: 99_999})
+      assert {:error, :invalid_payload} = Transform.decode(payload)
+    end
+
+    test "accepts nil width" do
+      payload = make_payload(%{hash: "abc", width: nil})
+      assert {:ok, %Transform{hash: "abc", width: nil}} = Transform.decode(payload)
+    end
+
+    test "accepts max allowed width 2048" do
+      payload = make_payload(%{hash: "abc", width: 2048})
+      assert {:ok, %Transform{hash: "abc", width: 2048}} = Transform.decode(payload)
+    end
+
+    test "accepts width 1" do
+      payload = make_payload(%{hash: "abc", width: 1})
+      assert {:ok, %Transform{hash: "abc", width: 1}} = Transform.decode(payload)
+    end
+  end
 end