Move common method to application concern

This could be potentially useful to all cluster applications.

Address followup issue https://gitlab.com/gitlab-org/gitlab-ce/issues/56524

app/models/clusters/applications/prometheus.rb

@@ -6,7 +6,6 @@ module Clusters
       include PrometheusAdapter
       VERSION = '6.7.3'
-      READY_STATUS = [:installed, :updating, :updated, :update_errored].freeze
       self.table_name = 'clusters_applications_prometheus'
@@ -25,10 +24,6 @@ module Clusters
         end
       end
-      def ready?
-        READY_STATUS.include?(status_name)
-      end
-
       def chart
         'stable/prometheus'
       end

app/models/clusters/concerns/application_status.rb

@@ -80,6 +80,10 @@ module Clusters
         installed? || updated?
       end
+      def ready?
+        installed? || updating? || updated? || update_errored?
+      end
+
       def update_in_progress?
         updating?
       end

spec/models/clusters/applications/prometheus_spec.rb

@@ -39,65 +39,6 @@ describe Clusters::Applications::Prometheus do
     end
   end
-  describe '#ready' do
-    let(:project) { create(:project) }
-    let(:cluster) { create(:cluster, projects: [project]) }
-
-    it 'returns true when installed' do
-      application = build(:clusters_applications_prometheus, :installed, cluster: cluster)
-
-      expect(application).to be_ready
-    end
-
-    it 'returns false when not_installable' do
-      application = build(:clusters_applications_prometheus, :not_installable, cluster: cluster)
-
-      expect(application).not_to be_ready
-    end
-
-    it 'returns false when installable' do
-      application = build(:clusters_applications_prometheus, :installable, cluster: cluster)
-
-      expect(application).not_to be_ready
-    end
-
-    it 'returns false when scheduled' do
-      application = build(:clusters_applications_prometheus, :scheduled, cluster: cluster)
-
-      expect(application).not_to be_ready
-    end
-
-    it 'returns false when installing' do
-      application = build(:clusters_applications_prometheus, :installing, cluster: cluster)
-
-      expect(application).not_to be_ready
-    end
-
-    it 'returns false when errored' do
-      application = build(:clusters_applications_prometheus, :errored, cluster: cluster)
-
-      expect(application).not_to be_ready
-    end
-
-    it 'returns true when updating' do
-      application = build(:clusters_applications_prometheus, :updating, cluster: cluster)
-
-      expect(application).to be_ready
-    end
-
-    it 'returns true when updated' do
-      application = build(:clusters_applications_prometheus, :updated, cluster: cluster)
-
-      expect(application).to be_ready
-    end
-
-    it 'returns true when errored' do
-      application = build(:clusters_applications_prometheus, :update_errored, cluster: cluster)
-
-      expect(application).to be_ready
-    end
-  end
-
   describe '#prometheus_client' do
     context 'cluster is nil' do
       it 'returns nil' do

spec/support/shared_examples/models/cluster_application_status_shared_examples.rb

@@ -138,6 +138,32 @@ shared_examples 'cluster application status specs' do |application_name|
     end
   end
+  describe '#ready?' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:trait, :ready) do
+      :not_installable  | false
+      :installable      | false
+      :scheduled        | false
+      :installing       | false
+      :installed        | true
+      :updating         | true
+      :updated          | true
+      :errored          | false
+      :update_errored   | true
+    end
+
+    with_them do
+      subject { build(application_name, trait) }
+
+      if params[:ready]
+        it { is_expected.to be_ready }
+      else
+        it { is_expected.not_to be_ready }
+      end
+    end
+  end
+
   describe '#available?' do
     using RSpec::Parameterized::TableSyntax