Fix issues mentioned but not closed for JIRA

The `ReferenceExtractor` would return an array of `ExternalIssue`
objects, and then perform `Array#-` to remove the issues
closed. `ExternalIssue`s had `==` defined, but not `hash` or `eql?`,
which are used by `Array#-`.

1 files changed, 8 insertions, 0 deletions

diff --git a/spec/models/external_issue_spec.rb b/spec/models/external_issue_spec.rb
index 2debe1289a3..cd50bda8996 100644
--- a/spec/models/external_issue_spec.rb
+++ b/spec/models/external_issue_spec.rb
@@ -42,4 +42,12 @@ describe ExternalIssue, models: true do
       expect(issue.project_id).to eq(project.id)
     end
   end
+
+  describe '#hash' do
+    it 'returns the hash of its [class, to_s] pair' do
+      issue_2 = described_class.new(issue.to_s, project)
+
+      expect(issue.hash).to eq(issue_2.hash)
+    end
+  end
 end