Class ToolTester

packages/testing/src/builders/tool-tester.builder.ts:113–416

 * Helper class for testing tools with controllable mock responses
 */
export class ToolTester<P = unknown, R = unknown> {
  tool: TestToolConfig<P, R>
  private mockFetch: MockFetch
  private originalFetch: typeof fetch
  private mockResponse: unknown
  private mockResponseOptions: { ok: boolean; status: number; headers: Record<string, string> }
  private error: Error | null = null

  constructor(tool: TestToolConfig<P, R>) {
    this.tool = tool
    this.mockResponse = { success: true, output: {} }
    this.mockResponseOptions = {
      ok: true,
      status: 200,
      headers: { 'content-type': 'application/json' },
    }
    this.mockFetch = createToolMockFetch(this.mockResponse, this.mockResponseOptions)
    this.originalFetch = global.fetch
  }

  /**
   * Setup mock responses for this tool
   */
  setup(
    response: unknown,
    options: { ok?: boolean; status?: number; headers?: Record<string, string> } = {}
  ) {
    this.mockResponse = response
    this.mockResponseOptions = {
      ok: options.ok ?? true,
      status: options.status ?? 200,
      headers: options.headers ?? { 'content-type': 'application/json' },
    }
    this.mockFetch = createToolMockFetch(this.mockResponse, this.mockResponseOptions)
    global.fetch = Object.assign(this.mockFetch, { preconnect: vi.fn() }) as typeof fetch
    return this
  }

  /**
   * Setup error responses for this tool
   */
  setupError(errorMessage: string, status = 400) {
    this.mockFetch = createErrorFetch(errorMessage, status)
    global.fetch = Object.assign(this.mockFetch, { preconnect: vi.fn() }) as typeof fetch

    this.error = new Error(errorMessage)
    ;(this.error as Error & { status: number }).status = status

    if (status > 0) {
      ;(this.error as Error & { response: unknown }).response = {
        ok: false,
        status,
        statusText: errorMessage,
        json: () => Promise.resolve({ error: errorMessage, message: errorMessage }),
      }
    }

    return this