Add tests for new git branch functionality

tests/test_git_diff.py

@@ -0,0 +1,410 @@
+"""
+Unit tests for git analysis functionality using pytest.
+"""
+
+from pathlib import Path
+from unittest.mock import Mock, PropertyMock, patch
+
+import pytest
+from git.exc import GitCommandError, InvalidGitRepositoryError
+
+from reviewllama.git_diff import (GitAnalysis, GitDiff, analyze_git_repository,
+                                  branch_exists, create_git_diff,
+                                  determine_change_type, extract_file_content,
+                                  filter_reviewable_diffs, find_git_repository,
+                                  get_base_branch, get_current_branch_name,
+                                  get_diff_between_branches,
+                                  process_diff_items)
+
+
+# Fixtures
+@pytest.fixture
+def mock_repo():
+    """Create a mock git repository."""
+    repo = Mock()
+    repo.active_branch.name = "feature-branch"
+    repo.head.commit.hexsha = "abc123def456"
+    return repo
+
+
+@pytest.fixture
+def mock_diff_item():
+    """Create a mock git diff item."""
+    diff = Mock()
+    diff.a_path = "src/main.py"
+    diff.b_path = "src/main.py"
+    diff.new_file = False
+    diff.deleted_file = False
+    diff.a_blob = Mock()
+    diff.b_blob = Mock()
+    diff.a_blob.data_stream.read.return_value = b"old content"
+    diff.b_blob.data_stream.read.return_value = b"new content"
+    diff.__str__ = Mock(return_value="diff content")
+    return diff
+
+
+@pytest.fixture
+def sample_git_diffs():
+    """Create sample GitDiff objects for testing."""
+    return [
+        GitDiff("src/main.py", "old", "new", "diff", "modified"),
+        GitDiff("test.js", "old", "new", "diff", "added"),
+        GitDiff("README.md", "old", "new", "diff", "modified"),
+        GitDiff("image.png", "old", "new", "diff", "added"),
+    ]
+
+
+# Tests for find_git_repository
+@patch('reviewllama.git_diff.Repo')
+def test_find_git_repository_success(mock_repo_class):
+    """Test successful git repository detection."""
+    mock_repo_instance = Mock()
+    mock_repo_class.return_value = mock_repo_instance
+    
+    path = Path("/project")
+    result = find_git_repository(path)
+    
+    mock_repo_class.assert_called_once_with(path, search_parent_directories=True)
+    assert result == mock_repo_instance
+
+
+@patch('reviewllama.git_diff.Repo')
+def test_find_git_repository_not_found(mock_repo_class):
+    """Test git repository not found."""
+    mock_repo_class.side_effect = InvalidGitRepositoryError()
+    
+    path = Path("/not-a-repo")
+    
+    with pytest.raises(ValueError, match="No git repository found"):
+        find_git_repository(path)
+
+
+# Tests for get_current_branch_name
+def test_get_current_branch_name_active_branch(mock_repo):
+    """Test getting current branch name from active branch."""
+    result = get_current_branch_name(mock_repo)
+    assert result == "feature-branch"
+
+
+def test_get_current_branch_name_detached_head(mock_repo):
+    """Test getting current branch name in detached HEAD state."""
+    type(mock_repo.active_branch).name = PropertyMock(side_effect=TypeError())
+    result = get_current_branch_name(mock_repo)
+    assert result == "abc123de"  # First 8 chars of hexsha
+
+
+# Tests for branch_exists
+def test_branch_exists_true(mock_repo):
+    """Test branch exists returns True when branch found."""
+    mock_repo.commit.return_value = Mock()
+    
+    result = branch_exists(mock_repo, "main")
+    assert result is True
+    mock_repo.commit.assert_called_once_with("main")
+
+
+def test_branch_exists_false(mock_repo):
+    """Test branch exists returns False when branch not found."""
+    mock_repo.commit.side_effect = Exception("Branch not found")
+    
+    result = branch_exists(mock_repo, "nonexistent")
+    assert result is False
+
+
+# Tests for get_base_branch
+@patch('reviewllama.git_diff.branch_exists')
+def test_get_base_branch_requested_exists(mock_branch_exists, mock_repo):
+    """Test get_base_branch returns requested branch when it exists."""
+    mock_branch_exists.return_value = True
+    
+    result = get_base_branch(mock_repo, "develop")
+    assert result == "develop"
+    mock_branch_exists.assert_called_once_with(mock_repo, "develop")
+
+
+@patch('reviewllama.git_diff.branch_exists')
+def test_get_base_branch_fallback_to_master(mock_branch_exists, mock_repo):
+    """Test get_base_branch falls back to master when requested not found."""
+    mock_branch_exists.side_effect = [False, True]  # requested=False, master=True
+    
+    result = get_base_branch(mock_repo, "nonexistent")
+    assert result == "master"
+
+
+@patch('reviewllama.git_diff.branch_exists')
+def test_get_base_branch_fallback_to_main(mock_branch_exists, mock_repo):
+    """Test get_base_branch falls back to main when master not found."""
+    mock_branch_exists.side_effect = [False, False, True]  # requested=False, master=False, main=True
+    
+    result = get_base_branch(mock_repo, "nonexistent")
+    assert result == "main"
+
+
+@patch('reviewllama.git_diff.branch_exists')
+def test_get_base_branch_no_fallback_found(mock_branch_exists, mock_repo):
+    """Test get_base_branch raises error when no fallback found."""
+    mock_branch_exists.return_value = False
+    
+    with pytest.raises(ValueError, match="Base branch 'nonexistent' not found"):
+        get_base_branch(mock_repo, "nonexistent")
+
+
+# Tests for get_diff_between_branches
+def test_get_diff_between_branches_success(mock_repo):
+    """Test successful diff between branches."""
+    base_commit = Mock()
+    current_commit = Mock()
+    mock_diff = Mock()
+    
+    mock_repo.commit.side_effect = [base_commit, current_commit]
+    base_commit.diff.return_value = mock_diff
+    
+    result = get_diff_between_branches(mock_repo, "master", "feature")
+    
+    assert result == mock_diff
+    base_commit.diff.assert_called_once_with(current_commit)
+
+
+def test_get_diff_between_branches_git_error(mock_repo):
+    """Test diff between branches with git error."""
+    mock_repo.commit.side_effect = GitCommandError("git", "error")
+    
+    with pytest.raises(ValueError, match="Failed to get diff"):
+        get_diff_between_branches(mock_repo, "master", "feature")
+
+
+# Tests for determine_change_type
+def test_determine_change_type_added():
+    """Test determine_change_type for added file."""
+    diff = Mock()
+    diff.new_file = True
+    diff.deleted_file = False
+    
+    result = determine_change_type(diff)
+    assert result == "added"
+
+
+def test_determine_change_type_deleted():
+    """Test determine_change_type for deleted file."""
+    diff = Mock()
+    diff.new_file = False
+    diff.deleted_file = True
+    
+    result = determine_change_type(diff)
+    assert result == "deleted"
+
+
+def test_determine_change_type_modified():
+    """Test determine_change_type for modified file."""
+    diff = Mock()
+    diff.new_file = False
+    diff.deleted_file = False
+    
+    result = determine_change_type(diff)
+    assert result == "modified"
+
+
+# Tests for extract_file_content
+def test_extract_file_content_old(mock_diff_item):
+    """Test extracting old file content."""
+    result = extract_file_content(mock_diff_item, is_old=True)
+    assert result == "old content"
+    mock_diff_item.a_blob.data_stream.read.assert_called_once()
+
+
+def test_extract_file_content_new(mock_diff_item):
+    """Test extracting new file content."""
+    result = extract_file_content(mock_diff_item, is_old=False)
+    assert result == "new content"
+    mock_diff_item.b_blob.data_stream.read.assert_called_once()
+
+
+def test_extract_file_content_none_blob():
+    """Test extracting content when blob is None."""
+    diff = Mock()
+    diff.a_blob = None
+    
+    result = extract_file_content(diff, is_old=True)
+    assert result == ""
+
+
+def test_extract_file_content_decode_error():
+    """Test extracting content with decode error."""
+    diff = Mock()
+    diff.a_blob.data_stream.read.side_effect = UnicodeDecodeError("utf-8", b"", 0, 1, "error")
+    
+    result = extract_file_content(diff, is_old=True)
+    assert result == ""
+
+
+# Tests for create_git_diff
+def test_create_git_diff(mock_diff_item):
+    """Test creating GitDiff from git diff item."""
+    result = create_git_diff(mock_diff_item)
+    
+    assert isinstance(result, GitDiff)
+    assert result.file_path == "src/main.py"
+    assert result.old_content == "old content"
+    assert result.new_content == "new content"
+    assert result.diff_text == "diff content"
+    assert result.change_type == "modified"
+
+
+def test_create_git_diff_unknown_path():
+    """Test creating GitDiff with unknown file path."""
+    diff = Mock()
+    diff.a_path = None
+    diff.b_path = None
+    diff.new_file = False
+    diff.deleted_file = False
+    diff.a_blob = None
+    diff.b_blob = None
+    diff.__str__ = Mock(return_value="diff")
+    
+    result = create_git_diff(diff)
+    assert result.file_path == "unknown"
+
+
+# Tests for process_diff_items
+def test_process_diff_items():
+    """Test processing multiple diff items."""
+    diff1 = Mock()
+    diff1.a_path = "file1.py"
+    diff1.b_path = "file1.py"
+    diff1.new_file = False
+    diff1.deleted_file = False
+    diff1.a_blob = None
+    diff1.b_blob = None
+    diff1.__str__ = Mock(return_value="diff1")
+    
+    diff2 = Mock()
+    diff2.a_path = "file2.py"
+    diff2.b_path = "file2.py"
+    diff2.new_file = True
+    diff2.deleted_file = False
+    diff2.a_blob = None
+    diff2.b_blob = None
+    diff2.__str__ = Mock(return_value="diff2")
+    
+    diff_index = [diff1, diff2]
+    
+    result = process_diff_items(diff_index)
+    
+    assert len(result) == 2
+    assert all(isinstance(diff, GitDiff) for diff in result)
+    assert result[0].file_path == "file1.py"
+    assert result[1].file_path == "file2.py"
+
+
+# Tests for filter_reviewable_diffs
+def test_filter_reviewable_diffs(sample_git_diffs):
+    """Test filtering reviewable diffs."""
+    result = filter_reviewable_diffs(sample_git_diffs)
+    
+    # Should include .py and .js files, exclude .md and .png
+    assert len(result) == 2
+    file_paths = [diff.file_path for diff in result]
+    assert "src/main.py" in file_paths
+    assert "test.js" in file_paths
+    assert "README.md" not in file_paths
+    assert "image.png" not in file_paths
+
+
+def test_filter_reviewable_diffs_empty():
+    """Test filtering reviewable diffs with empty input."""
+    result = filter_reviewable_diffs([])
+    assert result == []
+
+
+# Tests for analyze_git_repository
+@patch('reviewllama.git_diff.find_git_repository')
+@patch('reviewllama.git_diff.get_current_branch_name')
+@patch('reviewllama.git_diff.get_base_branch')
+@patch('reviewllama.git_diff.get_diff_between_branches')
+@patch('reviewllama.git_diff.process_diff_items')
+@patch('reviewllama.git_diff.filter_reviewable_diffs')
+def test_analyze_git_repository_success(
+    mock_filter, mock_process, mock_get_diff, mock_get_base,
+    mock_get_current, mock_find_repo, sample_git_diffs
+):
+    """Test successful git repository analysis."""
+    # Setup mocks
+    mock_repo = Mock()
+    mock_find_repo.return_value = mock_repo
+    mock_get_current.return_value = "feature-branch"
+    mock_get_base.return_value = "master"
+    mock_get_diff.return_value = Mock()
+    mock_process.return_value = sample_git_diffs
+    mock_filter.return_value = sample_git_diffs[:2]  # Filter to 2 items
+    
+    path = Path("/project")
+    result = analyze_git_repository(path, "main")
+    
+    # Verify result
+    assert isinstance(result, GitAnalysis)
+    assert result.repository_path == path
+    assert result.current_branch == "feature-branch"
+    assert result.base_branch == "master"
+    assert len(result.diffs) == 2
+    assert result.total_files_changed == 2
+    
+    # Verify function calls
+    mock_find_repo.assert_called_once_with(path)
+    mock_get_current.assert_called_once_with(mock_repo)
+    mock_get_base.assert_called_once_with(mock_repo, "main")
+    mock_get_diff.assert_called_once_with(mock_repo, "master", "feature-branch")
+
+
+@patch('reviewllama.git_diff.find_git_repository')
+def test_analyze_git_repository_not_found(mock_find_repo):
+    """Test git repository analysis when repo not found."""
+    mock_find_repo.side_effect = ValueError("No git repository found")
+    
+    path = Path("/not-a-repo")
+    
+    with pytest.raises(ValueError, match="No git repository found"):
+        analyze_git_repository(path, "")
+
+
+# Integration test
+def test_git_diff_dataclass():
+    """Test GitDiff dataclass creation and immutability."""
+    diff = GitDiff(
+        file_path="test.py",
+        old_content="old",
+        new_content="new", 
+        diff_text="diff",
+        change_type="modified"
+    )
+    
+    assert diff.file_path == "test.py"
+    assert diff.old_content == "old"
+    assert diff.new_content == "new"
+    assert diff.diff_text == "diff"
+    assert diff.change_type == "modified"
+    
+    # Test immutability
+    with pytest.raises(AttributeError):
+        diff.file_path = "changed.py"
+
+
+def test_git_diff_dataclass():
+    """Test GitAnalysis dataclass creation and immutability."""
+    diffs = [GitDiff("test.py", "old", "new", "diff", "modified")]
+    analysis = GitAnalysis(
+        repository_path=Path("/project"),
+        current_branch="feature",
+        base_branch="master",
+        diffs=diffs,
+        total_files_changed=1
+    )
+    
+    assert analysis.repository_path == Path("/project")
+    assert analysis.current_branch == "feature"
+    assert analysis.base_branch == "master"
+    assert len(analysis.diffs) == 1
+    assert analysis.total_files_changed == 1
+    
+    # Test immutability
+    with pytest.raises(AttributeError):
+        analysis.current_branch = "changed"