powerpoint-python-pptx-mcp tests.instructions.md

Testing Guidelines

These instructions apply to all test files in the tests/ directory.

Testing principles

• Test behavior, not implementation - Focus on what code does, not how
• Test both success and error cases - Happy path AND edge cases
• Keep tests independent - No test should depend on another
• Clean up resources - Use fixtures and teardown to clean up
• Make tests deterministic - No flaky tests allowed

Test structure pattern

import pytest
from mcp_server.tools.example import handle_example

@pytest.mark.unit  # or @pytest.mark.integration
@pytest.mark.asyncio
async def test_example_success(sample_pptx_path):
    """Test successful example operation.
    
    Given: Valid inputs
    When: Tool is invoked
    Then: Operation succeeds with expected result
    """
    # Arrange
    arguments = {
        "pptx_path": sample_pptx_path,
        "param": "value"
    }
    
    # Act
    result = await handle_example(arguments)
    
    # Assert
    assert result["success"] is True
    assert "data" in result
    assert result["data"]["field"] == "expected_value"

@pytest.mark.unit
@pytest.mark.asyncio
async def test_example_validation_error(sample_pptx_path):
    """Test error handling for invalid input.
    
    Given: Invalid parameter
    When: Tool is invoked
    Then: ValidationError is raised or error response returned
    """
    # Arrange
    arguments = {
        "pptx_path": sample_pptx_path,
        "param": None  # Invalid
    }
    
    # Act
    result = await handle_example(arguments)
    
    # Assert
    assert result["success"] is False
    assert result["error_type"] == "validation_error"

Pytest markers

Always use appropriate markers:

• @pytest.mark.unit - Fast, isolated unit tests
• @pytest.mark.integration - Tests with file I/O or multiple components
• @pytest.mark.slow - Tests that take >1 second
• @pytest.mark.benchmark - Performance benchmarks
• @pytest.mark.security - Security-focused tests