The test suite was failing on Rails 6.0 + Ruby 3 with errors like:
Expected "{\"errors\":\"#<ActiveModel::Errors:0x000055f2e6cb8188>\"}"
to include "{\"errors\":{".
The ActiveModel::Errors object wasn't being serialized to JSON as
expected, and this only happened with that combination of Ruby/Rails.
Upon further investigation, this was caused by a change in Ruby and
fixed in Rails in this PR: https://github.com/rails/rails/pull/39697
(which describes in more details the exact same problem and links to the
Ruby bug tracker with more information).
That fix was backported to 6-0-stable in June 2020, but hasn't been
officially released in a stable version yet: (there have been only
security fixes since then for 6.0)
75f6539d0e
Since the branch contains the fix, I'm pointing directly to it to get
the tests passing. We can't tell if there'll be a new stable 6.0 release
at this point, but hopefully yes, in which case we can go back at
pointing to it.
This allows us to remove the dependency on the XML serializer provided
by the external `activemodel-serializers-xml` gem, and eliminates the
following deprecation warning:
DEPRECATION WARNING: ActiveModel::Errors#to_xml is deprecated and
will be removed in Rails 6.2.
Please note: this does not mean Devise doesn't support XML, it simply
means our test suite will use JSON to test non-navigatable formats
instead of XML, for simplicity. Devise's job is not to test object
serialization, so as long as your objects properly serialize to
XML/JSON/any other format, it should work out of the box.
And remove dupe entry in the exclude matrix.
In order to get Ruby 3 working we needed to install `rexml` as part of
the test dependencies, only done on the main Gemfile (Rails 6.1) and the
6.0 versions. (which are the only ones supported by Ruby 3.)
Devise itself doesn't require `rexml` as it does nothing with it, but a
dependency we use during tests seem to require it. I was able to track
it down to omniauth-openid -> rack-openid -> ruby-openid requiring it:
13a88ad644/lib/openid/yadis/xrds.rb (L1)
So while we have tests using omniauth-openid, we'll need this require in
place as well. Ideally that upstream version of ruby-openid should have
it, but it seems that one isn't updated in a while.
Peter Goldstein