epub2pdf: title-based export names, .pdf download headers, security hardening (68 tests green)

tests/test_cli.py

@@ -0,0 +1,50 @@
+"""CLI entrypoint tests: `python app.py --cli <file> --output <dir>`.
+
+Run as a real subprocess (not in-process) so argparse, exit codes and
+stdout behavior are tested exactly as a user would invoke them.
+"""
+import os
+import sys
+import zipfile
+import subprocess
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+FIXTURE_EBOOK = ROOT / "test_book.epub"
+
+
+def _run_cli(*args):
+    env = dict(os.environ)
+    return subprocess.run(
+        [sys.executable, str(ROOT / "app.py"), *args],
+        capture_output=True,
+        text=True,
+        timeout=120,
+        env=env,
+        cwd=str(ROOT),
+    )
+
+
+def test_cli_convert_success(tmp_path):
+    out_dir = tmp_path / "out"
+    proc = _run_cli("--cli", str(FIXTURE_EBOOK), "--output", str(out_dir))
+    assert proc.returncode == 0, proc.stderr
+    assert "Saved:" in proc.stdout
+    pdfs = list(out_dir.glob("*.pdf"))
+    assert len(pdfs) == 1
+    assert pdfs[0].stat().st_size > 1024
+    assert pdfs[0].read_bytes()[:4] == b"%PDF"
+
+
+def test_cli_missing_file_exits_2(tmp_path):
+    proc = _run_cli("--cli", str(tmp_path / "nope.epub"), "--output", str(tmp_path))
+    assert proc.returncode == 2
+    assert "not found" in proc.stdout
+
+
+def test_cli_corrupt_epub_exits_1(tmp_path):
+    bad = tmp_path / "bad.epub"
+    bad.write_bytes(b"not a zip")
+    proc = _run_cli("--cli", str(bad), "--output", str(tmp_path))
+    assert proc.returncode == 1
+    assert "error:" in proc.stdout