🚀 Feature Request: Pages Function Template with Tests

[humphd]

Describe the solution

I'm writing Pages functions, and it's been a fairly smooth experience. However, as I now try to add tests, I'm finding a lack of useful examples, docs, etc.

For example, I want to invoke one of my Pages functions (e.g., a onRequestGet()) in a test and assert various things about the response. I'm unclear how one would do this outside of the Cloudflare runtime invoking it.

It seems like I somehow have to get/simulate an EventContext:

export type EventContext<Env, P extends string, Data> = {
  request: Request;
  functionPath: string;
  waitUntil: (promise: Promise<any>) => void;
  passThroughOnException: () => void;
  next: (input?: Request | string, init?: RequestInit) => Promise<Response>;
  env: Env & {
    ASSETS: {
      fetch: typeof fetch;
    };
  };
  params: Params<P>;
  data: Data;
};

Maybe there's some way to do this in Miniflare or Wrangler, etc. but the docs and existing examples I can find are all focused on how one would do this with a Worker vs. Pages Function.

It would be nice if at least one of the Templates you have in this repo included a simple example to show how you wire up a test for Pages functions.

There may be a better place for this issue to live, I'm not sure. I've also tried asking this on the CloudFlare Discord and Twitter as well.

[JacobMGEvans]

Greetings! I appreciate this suggestion, the testing story with Workers/Pages is something actively being worked on by the team. We have some hopeful prototypes but it is still early stages.

Cc: @mrbbot do you have any suggestions for the interim with Miniflare or something else?

[humphd]

So far, I've been testing my Pages Functions by calling a secondary function that lets avoid dealing with context of the direct call. For example:

import { getTokens } from "../token";

interface Env {
  JWT_SECRET: string;
}

export async function handleLogout({
  accessToken,
  idToken,
  JWT_SECRET,
}: {
  accessToken: string | null;
  idToken: string | null;
  JWT_SECRET: string;
}) {
   // ...
}

export const onRequestGet: PagesFunction<Env> = async ({ request, env }) => {
  const { JWT_SECRET } = env;
  const { accessToken, idToken } = getTokens(request);

  return handleLogout({ accessToken, idToken JWT_SECRET });
};

My tests are agains handleLogout, etc. vs. onRequest*(), which works, but obviously isn't ideal. I've also run into a roadblock with testing against mock R2 buckets.

I'll be interested to see how you progress with your work on testing.

[JacobMGEvans]

I think some of our testing framework stuff is still in the works and in planning.

cc: @admah

[jspspike]

As Jacob mentioned we have some things in the work for tests but for now it's recommended to use unstable_dev or invoke wrangler pages dev directly. Here is an example with pages using functions.

I'll leave this issue open as an issue to improve documentation around testing with pages

[admah]

@humphd I'm not sure if you're still interested in a solution for this, but we recently introduced a new way to test via Vitest - https://developers.cloudflare.com/workers/testing/vitest-integration/. #5288 has an example that might be able to help you using that new library.

[humphd]

@humphd I'm not sure if you're still interested in a solution for this, but we recently introduced a new way to test via Vitest - https://developers.cloudflare.com/workers/testing/vitest-integration/. #5288 has an example that might be able to help you using that new library.

I am, thank you for following up. I'll take a look!

[admah]

Great! Sorry for the delay. Let me know if that works.

[CarmenPopoviciu]

@humphd pls let us know if Adam's suggestion helped with your issue 🙏

[humphd]

New APIs look good. I won't have time to try implementing for a while, but I'm excited to try them when I do.

[CarmenPopoviciu]

sure thing! I'll go ahead and close this issue in favour of https://github.com/cloudflare/workers-sdk/issues/5288, which tracks the creation of an example for Pages Functions using @cloudflare/vitest-pool-workers. Feel free to re-open if you think necessary <3