If we have an error type that we're checking a substring against, we
should really be checking using ErrorContains to indicate the right
semantics to assert.
Mostly done using these transforms:
find . -type f -name "*_test.go" | \
xargs gofmt -w -r 'assert.Assert(t, is.ErrorContains(e, s)) -> assert.ErrorContains(t, e, s)'
find . -type f -name "*_test.go" | \
xargs gofmt -w -r 'assert.Assert(t, is.Contains(err.Error(), s)) -> assert.ErrorContains(t, err, s)'
find . -type f -name "*_test.go" | \
xargs gofmt -w -r 'assert.Check(t, is.Contains(err.Error(), s)) -> assert.Check(t, is.ErrorContains(err, s))'
As well as some small fixups to helpers that were doing
strings.Contains explicitly.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>