Use normal associations instead of polymorphic.

We can't properly use foreign keys on columns that are configured for
polymorphic associations which has disadvantages related to data
integrity and storage. Given we only use time tracking for Issues and
Merge Requests we're moving to the usage of regular associations.

1 files changed, 28 insertions, 0 deletions

diff --git a/spec/models/timelog_spec.rb b/spec/models/timelog_spec.rb
index f08935b6425..ebc694213b6 100644
--- a/spec/models/timelog_spec.rb
+++ b/spec/models/timelog_spec.rb
@@ -2,9 +2,37 @@ require 'rails_helper'
 
 RSpec.describe Timelog, type: :model do
   subject { build(:timelog) }
+  let(:issue) { create(:issue) }
+  let(:merge_request) { create(:merge_request) }
 
   it { is_expected.to be_valid }
 
   it { is_expected.to validate_presence_of(:time_spent) }
   it { is_expected.to validate_presence_of(:user) }
+
+  describe 'Issuable validation' do
+    it 'is invalid if issue_id and merge_request_id are missing' do
+      subject.attributes = { issue: nil, merge_request: nil }
+
+      expect(subject).to be_invalid
+    end
+
+    it 'is invalid if issue_id and merge_request_id are set' do
+      subject.attributes = { issue: issue, merge_request: merge_request }
+
+      expect(subject).to be_invalid
+    end
+
+    it 'is valid if only issue_id is set' do
+      subject.attributes = { issue: issue, merge_request: nil }
+
+      expect(subject).to be_valid
+    end
+
+    it 'is valid if only merge_request_id is set' do
+      subject.attributes = { merge_request: merge_request, issue: nil }
+
+      expect(subject).to be_valid
+    end
+  end
 end