Caption support (#2462)

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

pkg/scene/caption_test.go

@@ -0,0 +1,55 @@
+package scene
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var testExts = []string{"mkv", "mp4"}
+
+type testCase struct {
+	captionPath        string
+	expectedLang       string
+	expectedCandidates []string
+}
+
+var testCases = []testCase{
+	{
+		captionPath:        "/stash/video.vtt",
+		expectedLang:       LangUnknown,
+		expectedCandidates: []string{"/stash/video.mkv", "/stash/video.mp4"},
+	},
+	{
+		captionPath:        "/stash/video.en.vtt",
+		expectedLang:       "en",
+		expectedCandidates: []string{"/stash/video.mkv", "/stash/video.mp4"}, // lang code valid, remove en part
+	},
+	{
+		captionPath:        "/stash/video.test.srt",
+		expectedLang:       LangUnknown,
+		expectedCandidates: []string{"/stash/video.test.mkv", "/stash/video.test.mp4"}, // no lang code/lang code invalid test should remain
+	},
+	{
+		captionPath:        "C:\\videos\\video.fr.srt",
+		expectedLang:       "fr",
+		expectedCandidates: []string{"C:\\videos\\video.mkv", "C:\\videos\\video.mp4"},
+	},
+	{
+		captionPath:        "C:\\videos\\video.xx.srt",
+		expectedLang:       LangUnknown,
+		expectedCandidates: []string{"C:\\videos\\video.xx.mkv", "C:\\videos\\video.xx.mp4"}, // no lang code/lang code invalid xx should remain
+	},
+}
+
+func TestGenerateCaptionCandidates(t *testing.T) {
+	for _, c := range testCases {
+		assert.ElementsMatch(t, c.expectedCandidates, GenerateCaptionCandidates(c.captionPath, testExts))
+	}
+}
+
+func TestGetCaptionsLangFromPath(t *testing.T) {
+	for _, l := range testCases {
+		assert.Equal(t, l.expectedLang, GetCaptionsLangFromPath(l.captionPath))
+	}
+}