Add domain field into Clusters::Cluster

This is the 1st step for moving Auto DevOps domain into cluster
settings, whether is project or group.

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/52363

2 files changed, 30 insertions, 1 deletions

diff --git a/spec/factories/clusters/clusters.rb b/spec/factories/clusters/clusters.rb
index 3e2c0df8afb..a2e5f4862db 100644
--- a/spec/factories/clusters/clusters.rb
+++ b/spec/factories/clusters/clusters.rb
@@ -59,5 +59,9 @@ FactoryBot.define do
     trait :with_installed_helm do
       application_helm factory: %i(clusters_applications_helm installed)
     end
+
+    trait :with_domain do
+      domain 'example.com'
+    end
   end
 end
diff --git a/spec/models/clusters/cluster_spec.rb b/spec/models/clusters/cluster_spec.rb
index f447e64b029..0161db740ee 100644
--- a/spec/models/clusters/cluster_spec.rb
+++ b/spec/models/clusters/cluster_spec.rb
@@ -113,7 +113,7 @@ describe Clusters::Cluster do
     end
   end
 
-  describe 'validation' do
+  describe 'validations' do
     subject { cluster.valid? }
 
     context 'when validates name' do
@@ -252,6 +252,31 @@ describe Clusters::Cluster do
         end
       end
     end
+
+    describe 'domain validation' do
+      let(:cluster) { build(:cluster) }
+
+      subject { cluster }
+
+      context 'when cluster has domain' do
+        let(:cluster) { build(:cluster, :with_domain) }
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'when cluster has an invalid domain' do
+        let(:cluster) { build(:cluster, domain: 'not-valid-domain') }
+
+        it 'should add an error on domain' do
+          expect(subject).not_to be_valid
+          expect(subject.errors[:domain].first).to eq('is not a fully qualified domain name')
+        end
+      end
+
+      context 'when cluster does not have a domain' do
+        it { is_expected.to be_valid }
+      end
+    end
   end
 
   describe '.ancestor_clusters_for_clusterable' do