Add support for Bun

[alastrat]

What would you like?

Implement Cypress over Bun runtime.

Why is this needed?

As Bun adoption is rapidly increasing, compatibility with tools and frameworks like Cypress is a must.

Other

No response

[MikeMcC399]

@alastrat

• Please check out Cypress (post)install fails with "TypeError: undefined is not an object" oven-sh/bun#8658 which is waiting for Bun to provide an environment compatible to Node.js for the options which Cypress needs for its postinstall phase. As documented in Bun's Runtime > Node.js compatibility
  page, not all Node.js functions are available in Bun. You may like to up-vote the Bun issue.
• See also Support Bun: Running Bun Install in Docker gives The Cypress App could not be downloaded #28722.

[jennifer-shehane]

Duplicate of #28722

[MikeMcC399]

• The Bun compatibility issue Cypress (post)install fails with "TypeError: undefined is not an object" oven-sh/bun#8658 is not the only error condition.

• If the Cypress cache (for instance on Ubuntu ~/.cache/Cypress/13.6.6/Cypress) is already populated with the Cypress binary then cypress verify still fails if there is no Node.js installed. This could be the same or a different root cause as the issue Cypress (post)install fails with "TypeError: undefined is not an object" oven-sh/bun#8658, so possibly this issue is not a duplicate of Support Bun: Running Bun Install in Docker gives The Cypress App could not be downloaded #28722.

Edit:
bun cypress verify works in Bun v1.0.31 and later if the Cypress cache has already been populated. See below for further test results.

[MikeMcC399]

Tests

Testing Bun v1.0.35 against Cypress 13.7.1, without Node.js installed, shows the following results:

Action	Result	Workaround
bun add cypress	"The Cypress App could not be downloaded"	manually install Cypress binary
bun cypress verify	succeeds if Cypress binary manually downloaded	-
bun cypress open	Cypress Launchpad opens with animated cy icon. No testing type option displayed.	unknown
bun cypress run	No output. Process hangs.	unknown

Bun > Node.js compatibility lists implemented and missing Node.js functionality in Bun and states "Bun aims for complete Node.js API compatibility.". The missing functionality in Bun prevents Cypress from running without Node.js.

Although there is a workaround for the download issue (see also #28722) this does not allow Cypress to run without Node.js.

Installing Node.js in addition to Bun allows each of the above tested commands to work. (Note: this is not a statement of support. It is just a comment about observed test results.)

Conclusion

You may be able to use the package manager function of Bun instead of one of the other package managers (npm, pnpm and Yarn), however Bun does not (yet) provide a full substitute for the Node.js API. Node.js is required to run Cypress through Bun.

[jiridanek]

Works significantly better with bun 1.1:

$ sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.all.disable_ipv6 = 1
$ bun add cypress
bun add v1.1.0 (5903a614)

 + @types/bun@1.0.12

 installed cypress@13.7.2 with binaries:
  - cypress

 179 packages installed [102.30s]

$ bun cypress verify

✔  Verified Cypress! /home/jdanek/.cache/Cypress/13.7.2/Cypress

$ bun cypress open

DevTools listening on ws://127.0.0.1:41159/devtools/browser/c4f512de-b0e8-47ee-850f-8ebcc670fc35
(node:101572) ExperimentalWarning: `--experimental-loader` may be removed in the future; instead use `register()`:
--import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register("file%3A///home/jdanek/.cache/Cypress/13.7.2/Cypress/resources/app/node_modules/ts-node/esm/transpile-only.mjs", pathToFileURL("./"));'
(Use `node-20 --trace-warnings ...` to show where the warning was created)
(node:101666) ExperimentalWarning: `--experimental-loader` may be removed in the future; instead use `register()`:
--import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register("file%3A///home/jdanek/.cache/Cypress/13.7.2/Cypress/resources/app/node_modules/ts-node/esm/transpile-only.mjs", pathToFileURL("./"));'
(Use `node-20 --trace-warnings ...` to show where the warning was created)
GET /__/ 200 4.177 ms - -
GET /__/assets/index-bda26968.css 200 1.673 ms - -

... clicked around, found the e2e test samples, ran todo app tests ..., seems to work

$ bun cypress run

... started well, but got stuck at `  Running:  2-advanced-examples/actions.cy.js                                              (2 of 20)`

  Running:  1-getting-started/todo.cy.js                                                   (1 of 20)


  example to-do app
    ✓ displays two todo items by default (689ms)
    ✓ can add new todo items (431ms)
    ✓ can check off an item as completed (214ms)
    with a checked task
      ✓ can filter for uncompleted tasks (304ms)
      ✓ can filter for completed tasks (309ms)
      ✓ can delete all completed tasks (302ms)


  6 passing (4s)


  (Results)

  ┌────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ Tests:        6                                                                                │
  │ Passing:      6                                                                                │
  │ Failing:      0                                                                                │
  │ Pending:      0                                                                                │
  │ Skipped:      0                                                                                │
  │ Screenshots:  0                                                                                │
  │ Video:        false                                                                            │
  │ Duration:     4 seconds                                                                        │
  │ Spec Ran:     1-getting-started/todo.cy.js                                                     │
  └────────────────────────────────────────────────────────────────────────────────────────────────┘


────────────────────────────────────────────────────────────────────────────────────────────────────
                                                                                                    
  Running:  2-advanced-examples/actions.cy.js                                              (2 of 20)


  Actions

[jiridanek]

Installing Node.js in addition to Bun allows each of the above tested commands to work. (Note: this is not a statement of support. It is just a comment about observed test results.)

I have

$ node --version
v20.12.0

installed, so I guess disregard my previous comment, please