Shouldn't this be global instead of window (there is no window object in Node)

Afaik the mock will be cleaned up automatically if you use jest.spyOn:

jest.spyOn(global.console, 'error')

Hm good point, although it works 🤔 probably because jsdom env running in jest?

ah, that might be. Can you check if global works too? That seems more "right".

This should work:

jest.spyOn(global.console, 'error').mockReturnValue(undefined);

I'm not sure if spies can have their return values changed? But even if they can, the damage console.error does is a side effect and not its return value, so this won't help -- the method has to be replaced.

I'll switch it to global though if that still works! 👍

undefined is the return value of console.log(). It's just a shorthand for this:

jest.spyOn(global.console, 'error').mockImplementation(() => undefined)

Right, but console.error already returns undefined all on its own right? It's the side effect of printing to stdout that I'm trying to suppress, and changing its return value won't do that.

Both of these will suppress the side effect:

jest.spyOn(global.console, 'error').mockImplementation(() => undefined)
 # and
jest.spyOn(global.console, 'error').mockReturnValue(undefined);

Simply doing this won't:

jest.spyOn(global.console, 'error')

Ok looked into this and TIL you can stub a function in jest using spyOn ... did not expect mockImplementation that to work like that!

There is a built-in for this:

  expect(() => route[0].handler(mockReq)).toThrowError(BoomError);

There are different matchers. You might have to modify it a bit to make it work.

Yeah, unfortunately the ones I tried didn't work here because I want to test things about the rejected error. Where does BoomError come from in your example?

Where does BoomError come from in your example?

Fantasy land :) I just expected something like that to be available. But this works:

await expect(route[0].handler(mockReq)).rejects.toMatchObject({ isBoom: true });