confusing use of "unexpected success" when no errors are involved

[mvdan]

https://go.dev/play/p/XftIYAoec8W

with v0.14.1, I see:

=== RUN   TestNil
    prog.go:11: 
        error:
          unexpected success
        got:
          (*int)(nil)
[...]

=== RUN   TestNonNil
    prog.go:16: 
        error:
          got non-nil value
        got:
          &int(0)
[...]

TestNonNil works fine, but TestNil tells me "unexpected success". I got that message in a long test and I was really confused - what was succeeding? The line in question wasn't comparing error values at all.

I think it should say "got nil value" if the type in question does not satisfy the error interface.

[frankban]

The Not checker returns "unexpected success" when the wrapped checker succeeds.
I agree the message might be confusing. Not(Nil) (or NotNil) are used so often that perhaps it's a good idea to provide a better and less generic error for the specific case, which is what is done by the linked PR. Could you please take a look?

[mvdan]

Left a review :)

[frankban]

Tagged as v1.14.2