Implement attribute consistency check for LFS files

tests/check_lfs_attributes_test.py

@@ -0,0 +1,85 @@
+from __future__ import annotations
+
+import shutil
+
+import pytest
+
+from pre_commit_hooks.check_lfs_attributes import check_lfs_attributes, select_lfs_attr_files, \
+    select_lfs_tree_files
+from pre_commit_hooks.check_lfs_attributes import main
+from pre_commit_hooks.util import cmd_output
+from testing.util import git_commit
+
+
+@pytest.fixture
+def temp_git_dir_as_cwd(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        yield temp_git_dir
+
+
+def has_gitlfs():
+    return shutil.which('git-lfs') is not None
+
+
+xfailif_no_gitlfs = pytest.mark.xfail(
+    not has_gitlfs(), reason='This test requires git-lfs',
+)
+
+
+@xfailif_no_gitlfs
+def test_select_lfs_attr_files(temp_git_dir_as_cwd):  # pragma: no cover
+    cmd_output('git', 'lfs', 'install', '--local')
+    cmd_output('git', 'lfs', 'track', '*.bin')
+    assert select_lfs_attr_files(set()) == set()
+    assert select_lfs_attr_files({'b.txt'}) == set()
+    assert select_lfs_attr_files({'a.bin', 'b.txt'}) == {'a.bin'}
+
+
+@xfailif_no_gitlfs
+def test_select_lfs_tree_files(temp_git_dir_as_cwd):  # pragma: no cover
+    cmd_output('git', 'lfs', 'install', '--local')
+    cmd_output('git', 'lfs', 'track', '*.bin')
+    temp_git_dir_as_cwd.join('a.bin').write('a')
+    temp_git_dir_as_cwd.join('b.bin').write('b')
+    cmd_output('git', 'add', 'a.bin')
+    assert select_lfs_tree_files(set()) == set()
+    assert select_lfs_tree_files({'b.bin'}) == set()
+    assert select_lfs_tree_files({'a.bin', 'b.bin'}) == {'a.bin'}
+
+
+@xfailif_no_gitlfs
+def test_nothing_added(temp_git_dir):
+    with temp_git_dir.as_cwd():
+        assert check_lfs_attributes(['a.bin']) == 0
+
+
+@xfailif_no_gitlfs
+def test_add_as_lfs_object(temp_git_dir_as_cwd):  # pragma: no cover
+    temp_git_dir_as_cwd.join('a.bin').write('a')
+    cmd_output('git', 'lfs', 'install', '--local')
+    cmd_output('git', 'lfs', 'track', '*.bin')
+    cmd_output('git', 'add', 'a.bin')
+    assert main(('a.bin',)) == 0
+
+
+@xfailif_no_gitlfs
+def test_regular_object_but_tracked_by_lfs(temp_git_dir_as_cwd, capsys):  # pragma: no cover
+    temp_git_dir_as_cwd.join('a.bin').write('a')
+    cmd_output('git', 'lfs', 'install', '--local')
+    cmd_output('git', 'add', 'a.bin')
+    cmd_output('git', 'lfs', 'track', '*.bin')
+    assert main(('a.bin',)) == 1
+    out, _ = capsys.readouterr()
+    assert 'a.bin is tracked by LFS but added as a regular object' in out
+
+
+@xfailif_no_gitlfs
+def test_lfs_object_but_not_tracked(temp_git_dir_as_cwd, capsys):  # pragma: no cover
+    temp_git_dir_as_cwd.join('a.bin').write('a')
+    cmd_output('git', 'lfs', 'install', '--local')
+    cmd_output('git', 'lfs', 'track', '*.bin')
+    cmd_output('git', 'add', 'a.bin')
+    cmd_output('git', 'lfs', 'untrack', '*.bin')
+    assert main(('a.bin',)) == 1
+    out, _ = capsys.readouterr()
+    assert 'a.bin is added as LFS object but not tracked' in out