Address specs failing in rails 4

We want to run CI with rails 4 for a short-term (until we are sure that
we will ship with rails 5). The problem is that rails 4 can not handle
rails 5 schema.rb properly - specifically `t.index` directive can not
handle multiple indexes on the same column.

Because combination of rails 4 + rails 5 schema will be used
only in CI for a short-term, we can just ignore these incompatibility
failures. This patch adds `rails5` helper for specs.

1 files changed, 6 insertions, 1 deletions

diff --git a/spec/lib/gitlab/github_import/importer/pull_request_importer_spec.rb b/spec/lib/gitlab/github_import/importer/pull_request_importer_spec.rb
index 25684ea9e2c..efca8564894 100644
--- a/spec/lib/gitlab/github_import/importer/pull_request_importer_spec.rb
+++ b/spec/lib/gitlab/github_import/importer/pull_request_importer_spec.rb
@@ -240,7 +240,12 @@ describe Gitlab::GithubImport::Importer::PullRequestImporter, :clean_gitlab_redi
           .and_return(user.id)
       end
 
-      it 'returns the existing merge request' do
+      # TODO: remove rails5-only after removing rails4 tests
+      # rails 4 can not handle multiple indexes on the same column set if
+      # index was added by 't.index' - t.index is used by default in schema.rb in
+      # rails 5. Let's run this test only in rails 5 env:
+      # see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21492#note_113602758
+      it 'returns the existing merge request', :rails5 do
         mr1, exists1 = importer.create_merge_request
         mr2, exists2 = importer.create_merge_request