mockImplementationOnce behaves differently than mockImplementation

[cdanielsen]

🐛 Bug Report

mockImplementationOnce does not override a default implementation set with a beforeEach like mockImplementation does

To Reproduce

See the repl link below

Expected behavior

I would expect the calls to mockImlementationOnce would have the same effect as mockImplementation in this scenario

Link to repl or repo (highly encouraged)

https://repl.it/@cdanielsen/Possible-jest-mockImplementationOnce-bug

Run npx envinfo --preset jest

Looks like repl.it is using an older version of jest (22.1.2) but I was able to repro this issue with the following config on my local machine and also via a run with npx [email protected]

  System:
    OS: Linux 4.15 Ubuntu 18.04.2 LTS (Bionic Beaver)
    CPU: (3) x64 Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz
  Binaries:
    Node: 10.15.3 - ~/.nvm/versions/node/v10.15.3/bin/node
    Yarn: 1.12.3 - /usr/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v10.15.3/bin/npm
  npmPackages:
    jest: ^23.6.0 => 23.6.0

[jeysal]

Confirmed. Minimal repro:

  expect(
    jest
      .fn()
      .mockReturnValue(1)
      .mockImplementationOnce(() => 2)()
  ).toBe(2);

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.