test: add comprehensive tests for db reset command

- Test that reset command clears project configuration to defaults
- Test user cancellation behavior
- Test --reindex flag functionality
- Test handling of non-existent database files
- Follow existing test patterns and proper mocking

Co-authored-by: Paul Hernandez <phernandez@users.noreply.github.com>

Author: claude[bot]

tests/cli/test_db_commands.py

@@ -0,0 +1,128 @@
+"""Tests for database CLI commands."""
+
+from pathlib import Path
+from unittest.mock import patch, AsyncMock, MagicMock
+
+from typer.testing import CliRunner
+
+from basic_memory.cli.main import app as cli_app
+
+
+def test_reset_command_clears_project_configuration(config_manager, app_config):
+    """Test that the reset command clears project configuration to defaults."""
+    runner = CliRunner()
+    
+    # Set up initial configuration with multiple projects
+    config_manager.config.projects = {
+        "project1": "/path/to/project1",
+        "project2": "/path/to/project2",
+        "test-project": "/path/to/test"
+    }
+    config_manager.config.default_project = "project1"
+    
+    # Mock the confirmation to return True (user confirms reset)
+    with patch("basic_memory.cli.commands.db.typer.confirm", return_value=True):
+        # Mock the database file existence check and deletion
+        with patch("pathlib.Path.exists", return_value=True):
+            with patch("pathlib.Path.unlink") as mock_unlink:
+                # Mock the async db.run_migrations function
+                with patch("basic_memory.cli.commands.db.asyncio.run") as mock_run:
+                    mock_run.return_value = None
+                    
+                    # Run the reset command
+                    result = runner.invoke(cli_app, ["db", "reset"])
+                    
+                    # Should exit successfully
+                    assert result.exit_code == 0
+                    
+                    # Database file should be deleted
+                    mock_unlink.assert_called_once()
+                    
+                    # Async migrations should be called
+                    mock_run.assert_called_once()
+                    
+                    # Configuration should be reset to defaults
+                    expected_projects = {"main": str(Path.home() / "basic-memory")}
+                    assert config_manager.config.projects == expected_projects
+                    assert config_manager.config.default_project == "main"
+
+
+def test_reset_command_user_cancels(config_manager):
+    """Test that the reset command does nothing when user cancels."""
+    runner = CliRunner()
+    
+    # Set up initial configuration
+    original_projects = {
+        "project1": "/path/to/project1",
+        "project2": "/path/to/project2"
+    }
+    config_manager.config.projects = original_projects.copy()
+    config_manager.config.default_project = "project1"
+    
+    # Mock the confirmation to return False (user cancels)
+    with patch("basic_memory.cli.commands.db.typer.confirm", return_value=False):
+        with patch("pathlib.Path.unlink") as mock_unlink:
+            with patch("basic_memory.cli.commands.db.asyncio.run") as mock_run:
+                # Run the reset command
+                result = runner.invoke(cli_app, ["db", "reset"])
+                
+                # Should exit successfully
+                assert result.exit_code == 0
+                
+                # No database operations should occur
+                mock_unlink.assert_not_called()
+                mock_run.assert_not_called()
+                
+                # Configuration should remain unchanged
+                assert config_manager.config.projects == original_projects
+                assert config_manager.config.default_project == "project1"
+
+
+def test_reset_command_with_reindex(config_manager):
+    """Test that the reset command with --reindex flag calls sync."""
+    runner = CliRunner()
+    
+    # Mock the confirmation to return True
+    with patch("basic_memory.cli.commands.db.typer.confirm", return_value=True):
+        # Mock database operations
+        with patch("pathlib.Path.exists", return_value=True):
+            with patch("pathlib.Path.unlink"):
+                with patch("basic_memory.cli.commands.db.asyncio.run"):
+                    # Mock the sync command that gets imported and called
+                    with patch("basic_memory.cli.commands.db.sync") as mock_sync:
+                        # Run the reset command with reindex flag
+                        result = runner.invoke(cli_app, ["db", "reset", "--reindex"])
+                        
+                        # Should exit successfully
+                        assert result.exit_code == 0
+                        
+                        # Sync should be called with watch=False
+                        mock_sync.assert_called_once_with(watch=False)
+
+
+def test_reset_command_nonexistent_database(config_manager):
+    """Test reset command when database file doesn't exist."""
+    runner = CliRunner()
+    
+    # Mock the confirmation to return True
+    with patch("basic_memory.cli.commands.db.typer.confirm", return_value=True):
+        # Mock database file doesn't exist
+        with patch("pathlib.Path.exists", return_value=False):
+            with patch("pathlib.Path.unlink") as mock_unlink:
+                with patch("basic_memory.cli.commands.db.asyncio.run") as mock_run:
+                    # Run the reset command
+                    result = runner.invoke(cli_app, ["db", "reset"])
+                    
+                    # Should exit successfully
+                    assert result.exit_code == 0
+                    
+                    # Database file deletion should not be attempted
+                    mock_unlink.assert_not_called()
+                    
+                    # But migrations should still run
+                    mock_run.assert_called_once()
+                    
+                    # Configuration should still be reset
+                    expected_projects = {"main": str(Path.home() / "basic-memory")}
+                    assert config_manager.config.projects == expected_projects
+                    assert config_manager.config.default_project == "main"