feat: VTT-Untertitel in Rohabschrift umwandeln (vtt2txt.py)

- vtt2txt.py als Kommandozeilenprogramm: -i nimmt mehrere Dateien und
  Muster (auch ohne Shell-Expansion), -o eine Datei oder ein Verzeichnis
- Rollende YouTube-Untertitel über die Überlappung aufeinanderfolgender
  Blöcke entdoppeln; echte Wiederholungen des Redners bleiben erhalten
- Fix: Blöcke nur an wirklich leeren Zeilen trennen; Text nach einer
  Leerzeichen-Zeile ging verloren (u. a. das letzte [applaus])
- Schutz gegen Überschreiben der Eingabe und doppelte Ausgabedateien,
  klare Meldung bei Nicht-UTF-8, Stapel läuft bei Fehlern weiter
- rede_korrigieren.py nimmt .vtt direkt an
- testdaten/ramstein.de.txt neu erzeugt (+ abschließendes [applaus])
- pytest: global installiertes asyncio-Plugin abschalten (Warnung)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_vtt2txt.py

@@ -0,0 +1,157 @@
+"""Tests for vtt2txt.py."""
+import shutil
+import sys
+from pathlib import Path
+
+import pytest
+
+import vtt2txt
+
+REPO = Path(__file__).resolve().parent.parent
+SAMPLE_VTT = REPO / "testdaten" / "ramstein.de.vtt"
+SAMPLE_TXT = REPO / "testdaten" / "ramstein.de.txt"
+
+
+@pytest.fixture
+def sample_copy(tmp_path):
+    target = tmp_path / SAMPLE_VTT.name
+    shutil.copy(SAMPLE_VTT, target)
+    return target
+
+
+def cue(start, *lines):
+    return f"00:00:{start:02d}.000 --> 00:00:{start + 1:02d}.000\n" + "\n".join(lines) + "\n\n"
+
+
+def run_main(monkeypatch, *args):
+    monkeypatch.setattr(sys, "argv", ["vtt2txt.py", *map(str, args)])
+    vtt2txt.main()
+
+
+def test_vtt_to_lines_strips_tags_and_rolling_duplicates():
+    vtt = (
+        "WEBVTT\nKind: captions\n\n"
+        "00:00:01.000 --> 00:00:02.000 align:start\n"
+        "Erste<00:00:01.500><c> Zeile</c>\n\n"
+        "00:00:02.000 --> 00:00:03.000\nErste Zeile\n \n\n"
+        "cue-id\n00:00:03.000 --> 00:00:04.000\nErste Zeile\nA &amp; B\n"
+    )
+    assert vtt2txt.vtt_to_lines(vtt) == ["Erste Zeile", "A & B"]
+
+
+def test_vtt_to_lines_keeps_text_after_space_only_line():
+    # YouTube cues start with a line holding a single space; the text after it
+    # must survive even if no later cue repeats it (here: end of file)
+    vtt = "WEBVTT\n\n00:00:01.000 --> 00:00:02.000\n \n[applaus]\n"
+    assert vtt2txt.vtt_to_lines(vtt) == ["[applaus]"]
+
+
+def test_vtt_to_lines_skips_note_and_normalizes_whitespace():
+    vtt = (
+        "WEBVTT\n\nNOTE Kommentar\nnicht übernehmen\n\n"
+        "00:00:01.000 --> 00:00:02.000\nA&nbsp; B\n\n"
+        "00:00:02.000 --> 00:00:03.000\nA B\nC\n"
+    )
+    assert vtt2txt.vtt_to_lines(vtt) == ["A B", "C"]
+
+
+def test_vtt_to_lines_keeps_real_repetition():
+    # Rolling window: each cue repeats the previous line, then adds new text.
+    # The speaker really says "Nein." twice; both must survive.
+    vtt = "WEBVTT\n\n" + "".join([
+        cue(1, " ", "Er sagt:"),
+        cue(2, "Er sagt:", " "),
+        cue(3, "Er sagt:", "Nein."),
+        cue(4, "Nein.", " "),
+        cue(5, "Nein.", "Nein."),
+        cue(6, " ", " "),
+        cue(7, "Nein.", "Ende."),
+    ])
+    assert vtt2txt.vtt_to_lines(vtt) == ["Er sagt:", "Nein.", "Nein.", "Ende."]
+
+
+def test_vtt_to_lines_without_rolling_window():
+    vtt = "WEBVTT\n\n1\n" + cue(1, "A", "B") + "2\n" + cue(2, "C")
+    assert vtt2txt.vtt_to_lines(vtt) == ["A", "B", "C"]
+
+
+def test_main_default_output_matches_sample(sample_copy, monkeypatch, capsys):
+    run_main(monkeypatch, "-i", sample_copy)
+    target = sample_copy.with_name("ramstein.de.txt")
+    assert target.read_text(encoding="utf-8") == SAMPLE_TXT.read_text(encoding="utf-8")
+    assert f"Erstellt: {target}" in capsys.readouterr().out
+
+
+def test_main_multiple_inputs(sample_copy, monkeypatch):
+    second = sample_copy.with_name("rede.en.vtt")
+    shutil.copy(sample_copy, second)
+    run_main(monkeypatch, "-i", sample_copy, second)
+    assert sample_copy.with_suffix(".txt").is_file()
+    assert second.with_suffix(".txt").is_file()
+
+
+def test_main_expands_glob_without_duplicates(sample_copy, monkeypatch, capsys):
+    shutil.copy(sample_copy, sample_copy.with_name("ramstein.en.vtt"))
+    shutil.copy(sample_copy, sample_copy.with_name("anders.de.vtt"))
+    run_main(monkeypatch, "-i", sample_copy.parent / "ramstein.*.vtt", sample_copy)
+    out = capsys.readouterr().out
+    assert out.count("Erstellt:") == 2
+    assert not sample_copy.with_name("anders.de.txt").exists()
+
+
+@pytest.mark.parametrize("make_dir, suffix", [(True, ""), (False, "/")])
+def test_main_output_directory(sample_copy, monkeypatch, make_dir, suffix):
+    second = sample_copy.with_name("rede.en.vtt")
+    shutil.copy(sample_copy, second)
+    out_dir = sample_copy.parent / "out"
+    if make_dir:
+        out_dir.mkdir()
+    run_main(monkeypatch, "-i", sample_copy, second, "-o", f"{out_dir}{suffix}")
+    assert (out_dir / "ramstein.de.txt").is_file()
+    assert (out_dir / "rede.en.txt").is_file()
+
+
+def test_main_output_option_creates_directories(sample_copy, monkeypatch):
+    target = sample_copy.parent / "neu" / "unter" / "rede.txt"
+    run_main(monkeypatch, "-i", sample_copy, "-o", target)
+    assert target.is_file()
+
+
+@pytest.mark.parametrize("content, message", [
+    ("WEBVTT\n".encode("utf-8"), "Keine Untertitel"),
+    ("WEBVTT\n\n00:00:01.000 --> 00:00:02.000\nGrüße\n".encode("latin-1"),
+     "Keine UTF-8-Datei"),
+])
+def test_main_bad_file_continues_batch(sample_copy, monkeypatch, capsys, content, message):
+    bad = sample_copy.with_name("aaa.vtt")
+    bad.write_bytes(content)
+    with pytest.raises(SystemExit) as exc:
+        run_main(monkeypatch, "-i", bad, sample_copy)
+    assert exc.value.code == 1
+    assert message in capsys.readouterr().err
+    assert not bad.with_suffix(".txt").exists()
+    assert sample_copy.with_suffix(".txt").is_file()
+
+
+@pytest.mark.parametrize("args, message", [
+    ([], "required"),
+    (["-i", "gibtsnicht.vtt"], "Eingabedatei nicht gefunden"),
+    (["-i", "{txt}"], "Keine VTT-Datei"),
+    (["-i", "{vtt}", "{vtt2}", "-o", "{dir}/x.txt"], "muss -o/--output ein Verzeichnis sein"),
+    (["-i", "{dir}/*.gibtsnicht"], "Keine Datei passt zu"),
+    (["-i", "{vtt}", "{dir}/sub/ramstein.de.vtt", "-o", "{dir}/"], "dieselbe Ausgabedatei"),
+    (["-i", "{vtt}", "-o", "{vtt}"], "nicht die Eingabedatei"),
+])
+def test_cli_errors(sample_copy, monkeypatch, capsys, args, message):
+    txt = sample_copy.with_suffix(".txt")
+    txt.write_text("x\n", encoding="utf-8")
+    vtt2 = sample_copy.with_name("rede.en.vtt")
+    shutil.copy(sample_copy, vtt2)
+    (sample_copy.parent / "sub").mkdir()
+    shutil.copy(sample_copy, sample_copy.parent / "sub" / sample_copy.name)
+    args = [a.format(vtt=sample_copy, vtt2=vtt2, txt=txt, dir=sample_copy.parent)
+            for a in args]
+    with pytest.raises(SystemExit) as exc:
+        run_main(monkeypatch, *args)
+    assert exc.value.code == 2
+    assert message in capsys.readouterr().err