Updated review app button based on code review

Update ProjectPresenter.
Added rspec accordingly.
Removed changelog file.

app/presenters/project_presenter.rb

@@ -276,8 +276,8 @@ class ProjectPresenter < Gitlab::View::Presenter::Delegated
   end
 
   def kubernetes_cluster_anchor_data
-    if can_cluster_be_created?
-      if clusters_empty?
+    if can_instantiate_cluster?
+      if clusters.empty?
         AnchorData.new(false,
                        statistic_icon + _('Add Kubernetes cluster'),
                        new_project_cluster_path(project))
@@ -327,26 +327,26 @@ class ProjectPresenter < Gitlab::View::Presenter::Delegated
 
   def can_setup_review_app?
     strong_memoize(:can_setup_review_app) do
-      cicd_missing? || (can_cluster_be_created? && clusters_empty?)
+      (can_instantiate_cluster? && all_clusters_empty?) || cicd_missing?
     end
   end
 
-  def can_cluster_be_created?
-    current_user && can?(current_user, :create_cluster, project)
+  def all_clusters_empty?
+    strong_memoize(:all_clusters_empty) do
+      project.all_clusters.empty?
+    end
   end
 
+  private
+
   def cicd_missing?
     current_user && can_current_user_push_code? && repository.gitlab_ci_yml.blank? && !auto_devops_enabled?
   end
 
-  def clusters_empty?
-    strong_memoize(:cluster_missing) do
-      project.clusters.empty?
-    end
+  def can_instantiate_cluster?
+    current_user && can?(current_user, :create_cluster, project)
   end
 
-  private
-
   def filename_path(filename)
     if blob = repository.public_send(filename) # rubocop:disable GitlabSecurity/PublicSend
       project_blob_path(

app/serializers/review_app_setup_entity.rb

@@ -3,14 +3,14 @@
 class ReviewAppSetupEntity < Grape::Entity
   include RequestAwareEntity
 
-  expose :can_setup_review_app?
+  expose :can_setup_review_app?, as: :can_setup_review_app
 
-  expose :clusters_empty?, if: -> (_, _) { project.can_setup_review_app? } do |project|
-    project.clusters_empty?
+  expose :all_clusters_empty?, as: :all_clusters_empty, if: -> (_, _) { project.can_setup_review_app? } do |project|
+    project.all_clusters_empty?
   end
 
   expose :review_snippet, if: -> (_, _) { project.can_setup_review_app? } do |_|
-    YAML.safe_load(File.read(Rails.root.join('lib', 'gitlab', 'ci', 'snippets', 'review_app_default.yml'))).inspect
+    YAML.safe_load(File.read(Rails.root.join('lib', 'gitlab', 'ci', 'snippets', 'review_app_default.yml'))).to_s
   end
 
   private

changelogs/unreleased/118844-one-button-review-app-be.yml

----
-title: Provide backend support to show button for review app creation
-merge_request: 22085
-author:
-type: added

ee/spec/fixtures/api/schemas/review_app.json

 {
   "type": "object",
-  "required": ["can_setup_review_app?"],
+  "required": ["can_setup_review_app"],
   "properties": {
-    "can_setup_review_app?": { "type": "boolean" },
-    "clusters_empty?": { "type": "boolean" },
+    "can_setup_review_app": { "type": "boolean" },
+    "all_clusters_empty": { "type": "boolean" },
     "review_snippet": { "type": "string "}
   },
   "additionalProperties": false

spec/presenters/project_presenter_spec.rb

@@ -4,11 +4,10 @@ require 'spec_helper'
 
 describe ProjectPresenter do
   let(:user) { create(:user) }
-
-  describe '#license_short_name' do
   let(:project) { create(:project) }
   let(:presenter) { described_class.new(project, current_user: user) }
 
+  describe '#license_short_name' do
     context 'when project.repository has a license_key' do
       it 'returns the nickname of the license if present' do
         allow(project.repository).to receive(:license_key).and_return('agpl-3.0')
@@ -33,8 +32,6 @@ describe ProjectPresenter do
   end
 
   describe '#default_view' do
-    let(:presenter) { described_class.new(project, current_user: user) }
-
     context 'user not signed in' do
       let(:user) { nil }
 
@@ -125,7 +122,6 @@ describe ProjectPresenter do
 
   describe '#can_current_user_push_code?' do
     let(:project) { create(:project, :repository) }
-    let(:presenter) { described_class.new(project, current_user: user) }
 
     context 'empty repo' do
       let(:project) { create(:project) }
@@ -163,7 +159,6 @@ describe ProjectPresenter do
 
   context 'statistics anchors (empty repo)' do
     let(:project) { create(:project, :empty_repo) }
-    let(:presenter) { described_class.new(project, current_user: user) }
 
     describe '#files_anchor_data' do
       it 'returns files data' do
@@ -200,7 +195,6 @@ describe ProjectPresenter do
 
   context 'statistics anchors' do
     let(:project) { create(:project, :repository) }
-    let(:presenter) { described_class.new(project, current_user: user) }
 
     describe '#files_anchor_data' do
       it 'returns files data' do
@@ -416,7 +410,6 @@ describe ProjectPresenter do
 
   describe '#statistics_buttons' do
     let(:project) { build(:project) }
-    let(:presenter) { described_class.new(project, current_user: user) }
 
     it 'orders the items correctly' do
       allow(project.repository).to receive(:readme).and_return(double(name: 'readme'))
@@ -435,8 +428,6 @@ describe ProjectPresenter do
   end
 
   describe '#repo_statistics_buttons' do
-    let(:presenter) { described_class.new(project, current_user: user) }
-
     subject(:empty_repo_statistics_buttons) { presenter.empty_repo_statistics_buttons }
 
     before do
@@ -485,4 +476,73 @@ describe ProjectPresenter do
       end
     end
   end
+
+  describe '#can_setup_review_app?' do
+    subject { presenter.can_setup_review_app? }
+
+    context 'when the ci/cd file is missing' do
+      before do
+        allow(presenter).to receive(:cicd_missing?).and_return(true)
+      end
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when the ci/cd file is not missing' do
+      before do
+        allow(presenter).to receive(:cicd_missing?).and_return(false)
+      end
+
+      context 'and the user can create a cluster' do
+        before do
+          allow(Ability).to receive(:allowed?).and_call_original
+          allow(Ability).to receive(:allowed?).with(user, :create_cluster, project).and_return(true)
+        end
+
+        context 'and there is no cluster associated to this project' do
+          let(:project) { create(:project, clusters: []) }
+
+          it { is_expected.to be_truthy }
+        end
+
+        context 'and there is already a cluster associated to this project' do
+          let(:project) { create(:project, clusters: [build(:cluster, :providing_by_gcp)]) }
+
+          it { is_expected.to be_falsey }
+        end
+
+        context 'when a group cluster is instantiated' do
+          let_it_be(:cluster) { create(:cluster, :group) }
+          let_it_be(:group) { cluster.group }
+
+          context 'and the project belongs to this group' do
+            let!(:project) { create(:project, group: group) }
+
+            it { is_expected.to be_falsey }
+          end
+
+          context 'and the project does not belong to this group' do
+            it { is_expected.to be_truthy }
+          end
+        end
+
+        context 'and there is already an instance cluster' do
+          it 'is false' do
+            create(:cluster, :instance)
+
+            is_expected.to be_falsey
+          end
+        end
+      end
+
+      context 'and the user cannot create a cluster' do
+        before do
+          allow(Ability).to receive(:allowed?).and_call_original
+          allow(Ability).to receive(:allowed?).with(user, :create_cluster, project).and_return(false)
+        end
+
+        it { is_expected.to be_falsey }
+      end
+    end
+  end
 end

spec/serializers/review_app_setup_entity_spec.rb

@@ -17,8 +17,8 @@ describe ReviewAppSetupEntity do
   subject { entity.as_json }
 
   describe '#as_json' do
-    it 'contains can_setup_review_app?' do
-      expect(subject).to include(:can_setup_review_app?)
+    it 'contains can_setup_review_app' do
+      expect(subject).to include(:can_setup_review_app)
     end
 
     context 'when the user can setup a review app' do
@@ -27,19 +27,17 @@ describe ReviewAppSetupEntity do
       end
 
       it 'contains relevant fields' do
-        expect(subject.keys).to include(:clusters_empty?, :review_snippet)
+        expect(subject.keys).to include(:all_clusters_empty, :review_snippet)
       end
 
       it 'exposes the relevant review snippet' do
-        review_app_snippet = YAML.safe_load(File.read(Rails.root.join('lib', 'gitlab', 'ci', 'snippets', 'review_app_default.yml'))).inspect
+        review_app_snippet = YAML.safe_load(File.read(Rails.root.join('lib', 'gitlab', 'ci', 'snippets', 'review_app_default.yml'))).to_s
 
         expect(subject[:review_snippet]).to eq(review_app_snippet)
       end
 
       it 'exposes whether the project has associated clusters' do
-        allow(project).to receive(:clusters).and_return([])
-
-        expect(subject[:clusters_empty?]).to be_truthy
+        expect(subject[:all_clusters_empty]).to be_truthy
       end
     end
 
@@ -49,7 +47,7 @@ describe ReviewAppSetupEntity do
       end
 
       it 'does not expose certain fields' do
-        expect(subject.keys).not_to include(:clusters_empty?, :review_snippet)
+        expect(subject.keys).not_to include(:all_clusters_empty, :review_snippet)
       end
     end
   end