feat: implement tddai Python library for TDD workspace management

- Create comprehensive tddai package with workspace, issue fetcher, and test generator modules
- Add Python CLI interface (tddai_cli.py) to replace complex Makefile shell logic
- Update Makefile targets to use Python CLI for better maintainability
- Implement proper behavior-based tests instead of file existence checks
- Add workspace lifecycle management (create, active, finish, cleanup)
- Add issue fetching from Gitea API with error handling
- Add comprehensive test coverage with 19 passing tests
- Support environment variable configuration for different deployments

This addresses issue #11: Setup TDD workspace infrastructure
All tests pass and the system achieves green state before commit.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_issue_11_workspace_creation.py

@@ -0,0 +1,156 @@
+"""
+Test workspace creation functionality for TDD infrastructure.
+
+This test validates issue #11: Setup TDD workspace infrastructure
+- Tests workspace creation from issue numbers
+- Validates workspace structure and files
+- Ensures proper error handling
+"""
+
+import pytest
+import tempfile
+import shutil
+from pathlib import Path
+from unittest.mock import Mock, patch
+
+from tddai import WorkspaceManager, IssueFetcher, WorkspaceStatus, WorkspaceError, IssueError
+from tddai.config import TddaiConfig
+
+
+class TestWorkspaceCreation:
+    """Test suite for workspace creation functionality."""
+
+    @pytest.fixture
+    def temp_workspace(self):
+        """Create a temporary workspace for testing."""
+        temp_dir = Path(tempfile.mkdtemp())
+        config = TddaiConfig(workspace_dir=temp_dir / ".markitect_workspace")
+        yield config
+        shutil.rmtree(temp_dir)
+
+    @pytest.fixture
+    def mock_issue_data(self):
+        """Mock issue data for testing."""
+        return {
+            'number': 11,
+            'title': 'Setup TDD workspace infrastructure',
+            'body': 'Create workspace management system for TDD workflow',
+            'state': 'open',
+            'created_at': '2025-01-01T00:00:00Z',
+            'html_url': 'http://example.com/issues/11',
+            'assignee': None,
+            'labels': []
+        }
+
+    def test_workspace_manager_initialization(self, temp_workspace):
+        """Test that WorkspaceManager can be initialized."""
+        manager = WorkspaceManager(temp_workspace)
+        assert manager.config == temp_workspace
+
+    def test_workspace_status_clean_initially(self, temp_workspace):
+        """Test that workspace status is clean when no workspace exists."""
+        manager = WorkspaceManager(temp_workspace)
+        status = manager.get_status()
+        assert status == WorkspaceStatus.CLEAN
+
+    def test_workspace_creation_from_issue_data(self, temp_workspace, mock_issue_data):
+        """Test that workspace can be created from issue data."""
+        manager = WorkspaceManager(temp_workspace)
+
+        workspace = manager.create_workspace(mock_issue_data)
+
+        assert workspace.issue_number == 11
+        assert workspace.issue_title == 'Setup TDD workspace infrastructure'
+        assert workspace.workspace_dir == temp_workspace.workspace_dir
+
+        # Verify workspace status changes to active
+        status = manager.get_status()
+        assert status == WorkspaceStatus.ACTIVE
+
+    def test_workspace_directory_structure_created(self, temp_workspace, mock_issue_data):
+        """Test that workspace creates proper directory structure."""
+        manager = WorkspaceManager(temp_workspace)
+        workspace = manager.create_workspace(mock_issue_data)
+
+        assert workspace.workspace_dir.exists()
+        assert workspace.issue_dir.exists()
+        assert workspace.tests_dir.exists()
+
+    def test_workspace_metadata_files_created(self, temp_workspace, mock_issue_data):
+        """Test that workspace creates required metadata files."""
+        manager = WorkspaceManager(temp_workspace)
+        workspace = manager.create_workspace(mock_issue_data)
+
+        assert workspace.requirements_file.exists()
+        assert workspace.test_plan_file.exists()
+        assert temp_workspace.current_issue_path.exists()
+
+    def test_current_issue_metadata_content(self, temp_workspace, mock_issue_data):
+        """Test that current issue metadata is properly stored."""
+        manager = WorkspaceManager(temp_workspace)
+        manager.create_workspace(mock_issue_data)
+
+        current_workspace = manager.get_current_workspace()
+        assert current_workspace.issue_number == 11
+        assert current_workspace.issue_title == 'Setup TDD workspace infrastructure'
+        assert current_workspace.issue_state == 'open'
+
+    def test_workspace_prevents_multiple_active_issues(self, temp_workspace, mock_issue_data):
+        """Test that only one workspace can be active at a time."""
+        manager = WorkspaceManager(temp_workspace)
+        manager.create_workspace(mock_issue_data)
+
+        # Try to create another workspace
+        second_issue_data = mock_issue_data.copy()
+        second_issue_data['number'] = 12
+        second_issue_data['title'] = 'Different issue'
+
+        with pytest.raises(WorkspaceError, match="Workspace already active"):
+            manager.create_workspace(second_issue_data)
+
+    @patch('tddai.issue_fetcher.subprocess.run')
+    def test_issue_fetcher_handles_invalid_issue(self, mock_run, temp_workspace):
+        """Test error handling for invalid issue numbers."""
+        # Mock curl response for non-existent issue
+        mock_run.return_value.returncode = 0
+        mock_run.return_value.stdout = '{"message": "404 Not Found"}'
+
+        fetcher = IssueFetcher(temp_workspace)
+
+        with pytest.raises(IssueError, match="not found"):
+            fetcher.fetch_issue(999)
+
+    def test_workspace_cleanup(self, temp_workspace, mock_issue_data):
+        """Test that workspace can be cleaned up properly."""
+        manager = WorkspaceManager(temp_workspace)
+        manager.create_workspace(mock_issue_data)
+
+        # Verify workspace exists
+        assert manager.get_status() == WorkspaceStatus.ACTIVE
+
+        # Clean up
+        manager.cleanup_workspace()
+
+        # Verify workspace is clean
+        assert manager.get_status() == WorkspaceStatus.CLEAN
+        assert not temp_workspace.workspace_dir.exists()
+
+    def test_workspace_finish_moves_tests(self, temp_workspace, mock_issue_data):
+        """Test that finishing workspace moves tests to main directory."""
+        manager = WorkspaceManager(temp_workspace)
+        workspace = manager.create_workspace(mock_issue_data)
+
+        # Create a test file in workspace
+        test_file = workspace.tests_dir / "test_example.py"
+        test_file.write_text("# Test content")
+
+        # Finish workspace
+        finished_workspace = manager.finish_workspace()
+
+        assert finished_workspace.issue_number == 11
+        assert manager.get_status() == WorkspaceStatus.CLEAN
+
+        # Verify test was moved
+        main_test_file = temp_workspace.tests_dir / "test_example.py"
+        assert main_test_file.exists()
+        assert main_test_file.read_text() == "# Test content"