update

backend/tests/test_pdf_convert.py

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+"""PDF→Text-Konvertierung: pymupdf4llm primär, pdftotext-Fallback, mtime-Cache."""
+
+import os
+import time
+
+import fitz  # PyMuPDF
+import pytest
+
+import blocks as blx
+
+
+def _mini_pdf(path, text="Approximationsalgorithmen sind wichtig."):
+    doc = fitz.open()
+    page = doc.new_page()
+    page.insert_text((72, 72), text, fontsize=12)
+    doc.save(str(path))
+    doc.close()
+
+
+def test_convert_writes_markdown_txt(tmp_path):
+    _mini_pdf(tmp_path / "skript.pdf")
+    blx._convert_pdfs(tmp_path)
+    out = (tmp_path / "skript.txt").read_text(encoding="utf-8")
+    assert "Approximationsalgorithmen" in out
+
+
+def test_cache_skips_fresh_txt(tmp_path):
+    _mini_pdf(tmp_path / "a.pdf")
+    marker = tmp_path / "a.txt"
+    marker.write_text("MARKER", encoding="utf-8")
+    now = time.time() + 60
+    os.utime(marker, (now, now))
+    blx._convert_pdfs(tmp_path)
+    assert marker.read_text(encoding="utf-8") == "MARKER"  # nicht neu konvertiert
+
+
+def test_fallback_to_pdftotext(tmp_path, monkeypatch):
+    _mini_pdf(tmp_path / "b.pdf")
+    monkeypatch.setattr(blx, "_pdf_markdown", lambda p: None)
+    monkeypatch.setattr(blx, "_pdf_plaintext", lambda p: "fallback")
+    blx._convert_pdfs(tmp_path)
+    assert (tmp_path / "b.txt").read_text(encoding="utf-8") == "fallback"
+
+
+def test_ocr_languages_from_tessdata(tmp_path, monkeypatch):
+    import pymupdf
+
+    monkeypatch.setattr(pymupdf, "get_tessdata", lambda: str(tmp_path))
+    assert blx._ocr_languages() is None  # keine Sprachdaten → OCR aus
+    (tmp_path / "eng.traineddata").touch()
+    assert blx._ocr_languages() == "eng"
+    (tmp_path / "deu.traineddata").touch()
+    assert blx._ocr_languages() == "deu+eng"
+    monkeypatch.setattr(pymupdf, "get_tessdata", lambda: (_ for _ in ()).throw(RuntimeError()))
+    assert blx._ocr_languages() is None
+
+
+def test_fidelity_guard_prefers_faithful_plaintext():
+    plain = "Definition. P = {L ⊆ Σ | A ∈ L} und ≤ sowie häufig über. " * 20
+    # Markdown verlor die Formeln (Symbole weg) → plain gewinnt
+    md_lossy = "Definition. und sowie h¨aufig ¨uber. " * 20
+    text, tool = blx._pick_conversion(md_lossy, plain)
+    assert tool == "pdftotext"
+    # Markdown treu (Symbole + Länge da) → md gewinnt
+    md_ok = "# Def\n" + plain
+    text, tool = blx._pick_conversion(md_ok, plain)
+    assert tool == "pymupdf4llm"
+    # nur eine Quelle verfügbar
+    assert blx._pick_conversion(None, plain)[1] == "pdftotext"
+    assert blx._pick_conversion(md_ok, None)[1] == "pymupdf4llm"
+    assert blx._pick_conversion(None, None) is None