Scaffold Tests for an Existing Module

Generates correctly structured pytest tests for a tool, resource, or custom route already present in the codebase, using the exact patterns established in this project.

When to use

• A tool, resource, or route exists but has no test file
• An existing test file is missing error-path or edge-case coverage
• Unsure about fixture usage, assertion patterns, or how to test error responses

Step 1 — Detect the package name

Read pyproject.toml to find the current PACKAGE name.

Step 2 — Interview the user

Ask the following questions. Use vscode_askQuestions if available.

Step 3 — Read the source module

Read the source file to understand:

• Function/handler signature and parameter names
• Return type and error cases (ToolError, ResourceError, status codes)
• Default parameter values for optional arguments

Step 4 — Generate the test file

Use ./references/test-patterns.md for the exact assertion and fixture patterns for each module type.

Tool test file → tests/test_TOOL_NAME.py

• Success path with a representative input
• Default parameter path (if any parameters have defaults)
• Error path using raise_on_error=False and asserting result.is_error
• Uses the shared client fixture from conftest.py

Resource test file → tests/test_RESOURCE_NAME.py

• Success path reading the resource URI
• JSON field assertion for structured resources
• Not-found error path for templated resources using pytest.raises(McpError)

Route test file → tests/test_ROUTE_NAME.py

• Success path asserting status code and response body
• Error path for each documented error response
• Uses httpx.ASGITransport(app=mcp.http_app()) — import the route module for side effects

Step 5 — Validate

ruff check .
pytest tests/test_<name>.py -v

Fix any issues before reporting completion.

Step 6 — Report

Tell the user:

• The test file path
• How many test cases were generated
• Any scenarios that could not be auto-generated and require manual implementation