From dbe0e79f54a8f94350bc17050662d30da6cc6e6d Mon Sep 17 00:00:00 2001
From: Bryan Van Deusen <bryan.vandeusen@fabledsword.com>
Date: Thu, 30 Apr 2026 17:01:50 -0400
Subject: [PATCH] fix(lidarr): wrap MBID-lookup decode errors with
 ErrInvalidPayload + fill test gaps
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- Decode errors in LookupArtist/AlbumByMBID now wrap ErrInvalidPayload so
  callers can errors.Is the same way they do against the M5a methods.
- Tighten TestLookupAlbumByMBID_BadJSON to assert on ErrInvalidPayload.
- Add empty-mbid rejection tests for both methods.
- Add TestLookupArtistByMBID_EmptyArrayReturnsErrNotFound (only the album
  variant had the test before — symmetric coverage now).
- Normalize the network-error test's api key to key123 for consistency
  with the rest of delete_test.go.
---
 internal/lidarr/delete_test.go | 42 +++++++++++++++++++++++++++++++---
 internal/lidarr/lookup_mbid.go |  4 ++--
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/internal/lidarr/delete_test.go b/internal/lidarr/delete_test.go
index 78d6789c..db8d3822 100644
--- a/internal/lidarr/delete_test.go
+++ b/internal/lidarr/delete_test.go
@@ -86,8 +86,44 @@ func TestLookupAlbumByMBID_BadJSON(t *testing.T) {
 	defer srv.Close()
 
 	_, err := c.LookupAlbumByMBID(context.Background(), "x")
-	if err == nil {
-		t.Fatal("err = nil, want decode error")
+	if !errors.Is(err, ErrInvalidPayload) {
+		t.Errorf("err = %v, want ErrInvalidPayload", err)
+	}
+}
+
+func TestLookupAlbumByMBID_EmptyMBIDRejected(t *testing.T) {
+	c, srv := newTestClient(func(http.ResponseWriter, *http.Request) {
+		t.Error("server should not be called with empty mbid")
+	})
+	defer srv.Close()
+
+	if _, err := c.LookupAlbumByMBID(context.Background(), ""); err == nil {
+		t.Error("err = nil, want empty-mbid rejection")
+	}
+}
+
+func TestLookupArtistByMBID_EmptyArrayReturnsErrNotFound(t *testing.T) {
+	c, srv := newTestClient(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("[]"))
+	})
+	defer srv.Close()
+
+	_, err := c.LookupArtistByMBID(context.Background(), "x")
+	if !errors.Is(err, ErrNotFound) {
+		t.Errorf("err = %v, want ErrNotFound", err)
+	}
+}
+
+func TestLookupArtistByMBID_EmptyMBIDRejected(t *testing.T) {
+	c, srv := newTestClient(func(http.ResponseWriter, *http.Request) {
+		t.Error("server should not be called with empty mbid")
+	})
+	defer srv.Close()
+
+	if _, err := c.LookupArtistByMBID(context.Background(), ""); err == nil {
+		t.Error("err = nil, want empty-mbid rejection")
 	}
 }
 
@@ -158,7 +194,7 @@ func TestDeleteAlbum_5xxReturnsErrServerError(t *testing.T) {
 func TestDeleteAlbum_NetworkErrorReturnsErrUnreachable(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {}))
 	srv.Close() // server is closed; client should fail to connect
-	c := NewClient(srv.URL, "test-key")
+	c := NewClient(srv.URL, "key123")
 
 	err := c.DeleteAlbum(context.Background(), 42, true, true)
 	if !errors.Is(err, ErrUnreachable) {
diff --git a/internal/lidarr/lookup_mbid.go b/internal/lidarr/lookup_mbid.go
index 89e839c8..ecfc0e08 100644
--- a/internal/lidarr/lookup_mbid.go
+++ b/internal/lidarr/lookup_mbid.go
@@ -22,7 +22,7 @@ func (c *Client) LookupArtistByMBID(ctx context.Context, mbid string) (LidarrArt
 
 	var rows []LidarrArtist
 	if err := json.NewDecoder(resp.Body).Decode(&rows); err != nil {
-		return LidarrArtist{}, fmt.Errorf("lidarr: decode artist: %w", err)
+		return LidarrArtist{}, fmt.Errorf("%w: decode artist: %v", ErrInvalidPayload, err)
 	}
 	if len(rows) == 0 {
 		return LidarrArtist{}, ErrNotFound
@@ -45,7 +45,7 @@ func (c *Client) LookupAlbumByMBID(ctx context.Context, mbid string) (LidarrAlbu
 
 	var rows []LidarrAlbum
 	if err := json.NewDecoder(resp.Body).Decode(&rows); err != nil {
-		return LidarrAlbum{}, fmt.Errorf("lidarr: decode album: %w", err)
+		return LidarrAlbum{}, fmt.Errorf("%w: decode album: %v", ErrInvalidPayload, err)
 	}
 	if len(rows) == 0 {
 		return LidarrAlbum{}, ErrNotFound