test(ffmpeg): mp3 cover art tests

* test(ffmpeg): no codec mp3 tests

* test: update golden files

ffmpeg/ffmpeg_test.go

@@ -23,6 +23,11 @@ var files = []string{
 	"schizo_90.mp4",
 	"schizo_180.mp4",
 	"schizo_270.mp4",
+	"with_cover.mp3",
+}
+
+var noVideo = []string{
+	"no_cover.mp3",
 }
 
 var baseDir = "../testdata/"
@@ -99,3 +104,34 @@ func TestAVContext(t *testing.T) {
 		}
 	}
 }
+
+func TestNoVideo(t *testing.T) {
+	require.NoError(t, os.MkdirAll(baseDir+"golden/meta", 0755))
+	require.NoError(t, os.MkdirAll(baseDir+"golden/export", 0755))
+	for _, filename := range noVideo {
+		t.Run(filename, func(t *testing.T) {
+			ctx := context.Background()
+			path := baseDir + filename
+			reader, err := os.Open(path)
+			require.NoError(t, err)
+			stats, err := os.Stat(path)
+			require.NoError(t, err)
+			av, err := LoadAVContext(ctx, reader, stats.Size())
+			require.NoError(t, err)
+			defer av.Close()
+			require.Equal(t, ErrDecoderNotFound, av.ProcessFrames(-1))
+			meta := av.Metadata()
+			metaBuf, err := json.Marshal(meta)
+			require.NoError(t, err)
+			goldenFile := baseDir + "golden/meta/" + filename + ".meta.json"
+			if curr, err := os.ReadFile(goldenFile); err == nil {
+				assert.Equal(t, string(curr), string(metaBuf))
+			} else {
+				require.NoError(t, os.WriteFile(goldenFile, metaBuf, 0666))
+			}
+			buf, err := av.Export(3)
+			require.Empty(t, buf)
+			require.Equal(t, ErrDecoderNotFound, err)
+		})
+	}
+}