tests

Instruction file imported from shelbeely/self-improving-mcp (.github/instructions/tests.instructions.md). Copyright stays with the author.

Test file conventions (tests/)

Imports and structure

import { describe, expect, it, beforeEach, afterEach } from "bun:test";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { registerXxxTools } from "../../src/tools/xxx.js";

Helper pattern — every test file uses the same boilerplate

type ToolResult = {
  content: Array<{ type: string; text: string }>;
  isError?: boolean;
};
type ToolHandler = (args: Record<string, unknown>, extra?: unknown) => Promise<ToolResult>;
type RegisteredTools = Record<string, { handler: ToolHandler }>;

function makeServer(): McpServer {
  const server = new McpServer({ name: "test-xxx", version: "0.0.1" }, { capabilities: { tools: {} } });
  registerXxxTools(server);
  return server;
}

function getTool(server: McpServer, name: string): ToolHandler {
  return (server as unknown as { _registeredTools: RegisteredTools })._registeredTools[name].handler;
}

What to test for every tool

• Happy path — correct input returns the expected result.
• Error path — bad input returns isError: true with a useful message.
• Edge cases — empty input, path traversal attempts, file-not-found, ambiguous matches.

Filesystem tests (write/memory tools)

• Use a tmp-<suite> subdirectory inside REPO_ROOT as the workspace.
• Create it in beforeEach and remove it with rm -rf in afterEach.
• Never leave files on disk when tests finish.

Smoke test (tests/smoke.test.ts)

tests/smoke.test.ts asserts the exact count of registered tools via Object.keys(registeredTools).length. Update this number whenever a tool is added or removed.