For rubygem-simp-rake-helpers, GitLab CI-hosted spec tests fail on where Travis CI-hosted ones succeed.
A recent example is the 5.11.3 tag:
GitLab CI spec tests fail: https://gitlab.com/simp/rubygem-simp-rake-helpers/pipelines/148053642
(The GitLab CI project is relatively new, and the GitLab CI pipeline currently allows these tests to fail.)
It's likely that some of these spec tests still require rpm-build and friends installed in the test host's environment.