claude-code/packages/mcp-client/src/__tests__/connection.test.ts

import { describe, expect, test } from 'bun:test'
import {
  DEFAULT_CONNECTION_TIMEOUT_MS,
  MAX_MCP_DESCRIPTION_LENGTH,
  MAX_ERRORS_BEFORE_RECONNECT,
  isTerminalConnectionError,
  isMcpSessionExpiredError,
} from '../connection.js'

describe('connection constants', () => {
  test('has reasonable defaults', () => {
    expect(DEFAULT_CONNECTION_TIMEOUT_MS).toBe(30_000)
    expect(MAX_MCP_DESCRIPTION_LENGTH).toBe(2048)
    expect(MAX_ERRORS_BEFORE_RECONNECT).toBe(3)
  })
})

describe('isTerminalConnectionError', () => {
  test('detects ECONNRESET', () => {
    expect(isTerminalConnectionError('Connection reset: ECONNRESET')).toBe(true)
  })

  test('detects ETIMEDOUT', () => {
    expect(isTerminalConnectionError('Connection timed out: ETIMEDOUT')).toBe(
      true,
    )
  })

  test('detects EPIPE', () => {
    expect(isTerminalConnectionError('Broken pipe: EPIPE')).toBe(true)
  })

  test('detects EHOSTUNREACH', () => {
    expect(isTerminalConnectionError('Host unreachable: EHOSTUNREACH')).toBe(
      true,
    )
  })

  test('detects ECONNREFUSED', () => {
    expect(isTerminalConnectionError('Connection refused: ECONNREFUSED')).toBe(
      true,
    )
  })

  test('detects SSE disconnection messages', () => {
    expect(isTerminalConnectionError('SSE stream disconnected')).toBe(true)
    expect(isTerminalConnectionError('Failed to reconnect SSE stream')).toBe(
      true,
    )
  })

  test('detects terminated', () => {
    expect(isTerminalConnectionError('Process terminated')).toBe(true)
  })

  test('rejects non-terminal errors', () => {
    expect(isTerminalConnectionError('some random error')).toBe(false)
    expect(isTerminalConnectionError('')).toBe(false)
    expect(isTerminalConnectionError('timeout waiting for response')).toBe(
      false,
    )
  })
})

describe('isMcpSessionExpiredError', () => {
  test('detects 404 with JSON-RPC session-not-found code', () => {
    const error = new Error(
      'Not found: {"code":-32001,"message":"Session not found"}',
    )
    Object.assign(error, { code: 404 })
    expect(isMcpSessionExpiredError(error)).toBe(true)
  })

  test('detects 404 with spaced JSON-RPC code', () => {
    const error = new Error('Not found: {"code": -32001}')
    Object.assign(error, { code: 404 })
    expect(isMcpSessionExpiredError(error)).toBe(true)
  })

  test('rejects non-404 errors', () => {
    const error = new Error('{"code":-32001}')
    Object.assign(error, { code: 500 })
    expect(isMcpSessionExpiredError(error)).toBe(false)
  })

  test('rejects 404 without session code', () => {
    const error = new Error('Not found')
    Object.assign(error, { code: 404 })
    expect(isMcpSessionExpiredError(error)).toBe(false)
  })

  test('rejects errors without code property', () => {
    const error = new Error('Session not found')
    expect(isMcpSessionExpiredError(error)).toBe(false)
  })
})