From 2b6fbda4d44f87b178b3b39580069423134f5d31 Mon Sep 17 00:00:00 2001
From: Mateus Bastos <mbdossantos07@gmail.com>
Date: Fri, 20 Jun 2025 20:03:21 -0300
Subject: [PATCH] test: Add unit tests for download_and_append_fragments

---
 test/test_fragment_fd_mcdc.py | 146 ++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 test/test_fragment_fd_mcdc.py

diff --git a/test/test_fragment_fd_mcdc.py b/test/test_fragment_fd_mcdc.py
new file mode 100644
index 000000000..f9f241cb3
--- /dev/null
+++ b/test/test_fragment_fd_mcdc.py
@@ -0,0 +1,146 @@
+import pytest
+import time
+from yt_dlp.downloader.fragment import FragmentFD
+from yt_dlp.utils import DownloadError
+from unittest.mock import Mock
+
+
+class DummyDestStream:
+    def __init__(self):
+        self.contents = []
+
+    def write(self, data):
+        self.contents.append(data)
+
+    def flush(self):
+        pass
+
+    def close(self):
+        pass
+
+
+@pytest.fixture
+def dummy_ctx():
+    return {
+        'filename': 'testfile',
+        'fragment_index': 0,
+        'dest_stream': DummyDestStream(),
+        'live': False,
+        'tmpfilename': 'testfile.part',
+        'started': time.time(),
+        'total_bytes': 0,
+    }
+
+
+@pytest.fixture
+def dummy_info_dict():
+    return {
+        'http_headers': {},
+    }
+
+
+@pytest.fixture
+def dummy_fragment():
+    return {
+        'frag_index': 0,
+        'url': 'http://dummy.url/frag0.ts',
+        'fragment_count': 1,
+    }
+
+
+@pytest.fixture
+def fd():
+    fake_ydl = Mock()
+    fake_ydl._progress_hooks = []
+    fake_ydl._postprocessors = []
+    for name in [
+        'deprecation_warning', 'report_error', 'report_warning',
+        'to_screen', 'to_console_title',
+    ]:
+        setattr(fake_ydl, name, Mock())
+
+    return FragmentFD(fake_ydl, {
+        'fragment_retries': 0,
+        'skip_unavailable_fragments': True,
+        'noprogress': True,
+    })
+
+
+def test_ct1_fragment_ok(fd, dummy_ctx, dummy_info_dict, dummy_fragment, monkeypatch):
+    """CT1 - Fragmento comum, leitura e escrita sem falhas"""
+
+    dummy_fragment['url'] = 'http://example.com/video-frag.ts'
+
+    monkeypatch.setattr(fd, '_download_fragment', lambda *a, **k: True)
+    monkeypatch.setattr(fd, '_read_fragment', lambda ctx: b'data')
+    monkeypatch.setattr(fd, '_append_fragment', lambda ctx, content: ctx['dest_stream'].write(content))
+    monkeypatch.setattr(fd, 'try_rename', lambda *a, **k: None)
+    monkeypatch.setattr(fd.ydl, 'run_all_postprocessors', lambda *a, **k: ([], True))
+
+    fd.decrypter = lambda info: lambda fragment, content: content
+
+    result = fd.download_and_append_fragments(dummy_ctx, [dummy_fragment], dummy_info_dict)
+
+    assert dummy_ctx['dest_stream'].contents == [b'data']
+    assert result is False
+
+
+def test_ct2_fragment_skip(fd, dummy_ctx, dummy_info_dict, dummy_fragment, monkeypatch):
+    """CT2 - Fragmento falha na leitura, mas não é fatal: deve ser ignorado"""
+
+    dummy_fragment['frag_index'] = 1
+    dummy_fragment['byte_range'] = {'start': 0, 'end': 999}
+
+    monkeypatch.setattr(fd, '_download_fragment', lambda *a, **k: True)
+    monkeypatch.setattr(fd, '_read_fragment', lambda ctx: None)
+    monkeypatch.setattr(fd, 'try_rename', lambda *a, **k: None)
+    monkeypatch.setattr(fd.ydl, 'run_all_postprocessors', lambda *a, **k: ([], True))
+
+    skipped = []
+    monkeypatch.setattr(fd, 'report_skip_fragment', lambda idx, reason=None: skipped.append(idx))
+
+    fd.decrypter = lambda info: lambda fragment, content: content
+
+    result = fd.download_and_append_fragments(dummy_ctx, [dummy_fragment], dummy_info_dict)
+
+    assert skipped == [1]
+    assert result is False
+
+
+def test_ct3_fragment_fatal_error(fd, dummy_ctx, dummy_info_dict, dummy_fragment, monkeypatch):
+    """CT3 - Falha de leitura fatal: deve interromper o processo"""
+
+    monkeypatch.setattr(fd, '_download_fragment', lambda *a, **k: True)
+    monkeypatch.setattr(fd, '_read_fragment', lambda ctx: None)
+    monkeypatch.setattr(fd, '_append_fragment', lambda ctx, c: (_ for _ in ()).throw(Exception("Shouldn't append")))
+
+    fd.decrypter = lambda info: lambda fragment, content: content
+
+    errors = []
+    monkeypatch.setattr(fd, 'report_error', lambda msg, **kwargs: errors.append(msg))
+
+    def is_fatal(index):
+        return True
+
+    result = fd.download_and_append_fragments(dummy_ctx, [dummy_fragment], dummy_info_dict, is_fatal=is_fatal)
+
+    assert result is False
+    assert any('fragment' in e.lower() and 'unable to continue' in e.lower() for e in errors)
+
+
+def test_ct4_downloaderror_fatal(fd, dummy_ctx, dummy_info_dict, dummy_fragment, monkeypatch):
+    """CT4 - Erro de download fatal: exceção deve ser lançada"""
+
+    def raise_download_error(*a, **k):
+        raise DownloadError('Erro no download do fragmento')
+
+    monkeypatch.setattr(fd, '_download_fragment', raise_download_error)
+    monkeypatch.setattr(fd, '_read_fragment', lambda ctx: b'data')  # Nunca será chamado
+
+    fd.decrypter = lambda info: lambda fragment, content: content
+
+    def is_fatal(index):
+        return True
+
+    with pytest.raises(DownloadError, match='Erro no download'):
+        fd.download_and_append_fragments(dummy_ctx, [dummy_fragment], dummy_info_dict, is_fatal=is_fatal)