Move the package into src/

Thirty-seven entries in the root, most of them .go files. The assets had to
come along: //go:embed cannot reach outside its own directory, so
templates/, static/ and migrations/ live beside the code that embeds them,
and testdata/ beside the test that reads it. storage/ stays put — runtime
data, not source.

go build now needs -o. Without it the output would be named after the
package directory and collide with src/ itself.

src/lyrics_test.go

@@ -0,0 +1,112 @@
+package main
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+// Line breaks are the content here — LRC timestamps are per line — so cleanLyrics must not do what
+// clean() does to a title.
+func TestCleanLyrics(t *testing.T) {
+	got := cleanLyrics("  [00:11.74] Rivi yksi\r\n[00:13.99] Rivi\x07 kaksi\r\n\n")
+	want := "[00:11.74] Rivi yksi\n[00:13.99] Rivi kaksi"
+	if got != want {
+		t.Fatalf("cleanLyrics gave %q, want %q", got, want)
+	}
+	if n := len([]rune(cleanLyrics(strings.Repeat("a", maxLyrics+500)))); n != maxLyrics {
+		t.Fatalf("truncated to %d runes, want %d", n, maxLyrics)
+	}
+}
+
+// Plain text must parse to nil: that is the signal to scroll continuously rather than highlight
+// lines on timings nobody measured.
+func TestParseLRC(t *testing.T) {
+	if got := parseLRC("Ihan tavallista tekstiä\ntoinen rivi"); got != nil {
+		t.Fatalf("plain text parsed as synced: %v", got)
+	}
+
+	lines := parseLRC("[00:11.74] Ensimmäinen\n[01:02] Toinen\n[00:05.5] Aikaisempi\nrivi ilman aikaa")
+	if len(lines) != 3 {
+		t.Fatalf("got %d lines, want 3 — untimed lines are dropped", len(lines))
+	}
+	// Sorted by time, whatever order the file had.
+	if lines[0].At != 5.5 || lines[0].Text != "Aikaisempi" {
+		t.Fatalf("first line is %+v, want 5.5s Aikaisempi", lines[0])
+	}
+	if lines[1].At != 11.74 || lines[2].At != 62 {
+		t.Fatalf("timestamps parsed as %v and %v, want 11.74 and 62", lines[1].At, lines[2].At)
+	}
+
+	// A refrain can carry several timestamps on one line, and each is its own occurrence.
+	rep := parseLRC("[00:10.00][01:10.00] Kertosäe")
+	if len(rep) != 2 || rep[0].At != 10 || rep[1].At != 70 {
+		t.Fatalf("repeated stamps gave %+v, want two occurrences", rep)
+	}
+}
+
+// The lookup is a suggestion, so "nothing found" is a normal answer rather than an error, and a
+// synced hit always beats a plain one.
+func TestFetchLyrics(t *testing.T) {
+	var lastPath string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		lastPath = r.URL.Path
+		w.Header().Set("Content-Type", "application/json")
+		switch {
+		case r.URL.Path == "/get" && r.URL.Query().Get("track_name") == "Paranoid":
+			w.Write([]byte(`{"trackName":"Paranoid","artistName":"Black Sabbath","duration":168,
+			                 "plainLyrics":"plain version","syncedLyrics":"[00:11.74] synced version"}`))
+		case r.URL.Path == "/get":
+			http.Error(w, `{"code":404}`, http.StatusNotFound)
+		case r.URL.Path == "/search" && strings.Contains(r.URL.Query().Get("q"), "Soittorasia"):
+			// An instrumental and a wrong-length take come first: both must be skipped.
+			w.Write([]byte(`[{"trackName":"Soittorasia","duration":200,"instrumental":true,
+			                  "plainLyrics":"","syncedLyrics":"[00:01.00] should be skipped"},
+			                 {"trackName":"Soittorasia","duration":600,
+			                  "plainLyrics":"wrong length take"},
+			                 {"trackName":"Soittorasia","duration":201,
+			                  "plainLyrics":"right one"}]`))
+		default:
+			w.Write([]byte(`[]`))
+		}
+	}))
+	defer srv.Close()
+
+	old := lrclibBase
+	lrclibBase = srv.URL
+	defer func() { lrclibBase = old }()
+
+	ctx := context.Background()
+
+	got, err := fetchLyrics(ctx, "Paranoid", "Black Sabbath", 168)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "[00:11.74] synced version" {
+		t.Fatalf("exact match returned %q, want the synced version", got)
+	}
+
+	got, err = fetchLyrics(ctx, "Soittorasia", "Joku", 200)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "right one" {
+		t.Fatalf("search fallback returned %q — instrumental and wrong-length takes must be skipped", got)
+	}
+	if lastPath != "/search" {
+		t.Fatalf("last request was %s, want the search fallback", lastPath)
+	}
+
+	// Nothing found is not an error: the submitter simply types their own.
+	got, err = fetchLyrics(ctx, "Ei olemassa", "Kukaan", 100)
+	if err != nil || got != "" {
+		t.Fatalf("miss returned %q, %v — want empty and no error", got, err)
+	}
+
+	// No title means nothing to match on, and no request at all.
+	if got, err := fetchLyrics(ctx, "", "Artisti", 100); err != nil || got != "" {
+		t.Fatalf("empty title returned %q, %v", got, err)
+	}
+}