BLACK DYNAMITE•3w ago

how to best test trpc?

does programs like postman not work well with trpc? if i wanted to test my trpc server by making requests, what the best way to do that?

1 Reply

y_nk•2w ago

i've found that best is to use the trpc client in your test runner (vitest/jest) by setting up the trpc client to use a custom http link which uses supertest with your app passed as param. with fastify (but it works with express too):

export function createTestClient(app: FastifyInstance) {
  const agent = supertest.agent(app.server)

  return createTRPCClient<AppRouter>({
    links: [
      httpLink({
        transformer: superjson,
        url: 'http://localhost/api',
        async fetch(input, options) {
          const method = options?.method?.toLowerCase() ?? 'get'
          const url = new URL(input)

          let call = agent[method](`${url.pathname}${url.search}`)

          // Add headers
          if (options?.headers) {
            for (const [key, val] of Object.entries(options.headers)) {
              call = call.set(key, val)
            }
          }

          if (options?.body) {
            call = call.send(options.body)
          }

          const res = await call

          return new Response(JSON.stringify(res.body), {
            status: res.status,
            headers: res.headers,
          })
        },
      }),
    ],
  })
}

export function createTestClient(app: FastifyInstance) {
  const agent = supertest.agent(app.server)

  return createTRPCClient<AppRouter>({
    links: [
      httpLink({
        transformer: superjson,
        url: 'http://localhost/api',
        async fetch(input, options) {
          const method = options?.method?.toLowerCase() ?? 'get'
          const url = new URL(input)

          let call = agent[method](`${url.pathname}${url.search}`)

          // Add headers
          if (options?.headers) {
            for (const [key, val] of Object.entries(options.headers)) {
              call = call.set(key, val)
            }
          }

          if (options?.body) {
            call = call.send(options.body)
          }

          const res = await call

          return new Response(JSON.stringify(res.body), {
            status: res.status,
            headers: res.headers,
          })
        },
      }),
    ],
  })
}

how to best test trpc?

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