Refactor code around scheduling cluster installations

app/controllers/projects/clusters/applications_controller.rb

@@ -5,9 +5,10 @@ class Projects::Clusters::ApplicationsController < Projects::ApplicationControll
   before_action :authorize_create_cluster!, only: [:create]
 
   def create
-    Clusters::Applications::ScheduleInstallationService.new(project, current_user,
-                                                            application_class: @application_class,
-                                                            cluster: @cluster).execute
+    application = @application_class.find_or_create_by!(cluster: @cluster)
+
+    Clusters::Applications::ScheduleInstallationService.new(project, current_user).execute(application)
+
     head :no_content
   rescue StandardError
     head :bad_request

app/services/clusters/applications/schedule_installation_service.rb

 module Clusters
   module Applications
     class ScheduleInstallationService < ::BaseService
-      def execute
-        application_class.find_or_create_by!(cluster: cluster).try do |application|
-          application.make_scheduled!
-          ClusterInstallAppWorker.perform_async(application.name, application.id)
-        end
-      end
-
-      private
-
-      def application_class
-        params[:application_class]
-      end
+      def execute(application)
+        application.make_scheduled!
 
-      def cluster
-        params[:cluster]
+        ClusterInstallAppWorker.perform_async(application.name, application.id)
       end
     end
   end

spec/services/clusters/applications/schedule_installation_service_spec.rb

@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe Clusters::Applications::ScheduleInstallationService do
   def count_scheduled
-    application_class&.with_status(:scheduled)&.count || 0
+    application&.class&.with_status(:scheduled)&.count || 0
   end
 
   shared_examples 'a failing service' do
@@ -10,45 +10,42 @@ describe Clusters::Applications::ScheduleInstallationService do
       expect(ClusterInstallAppWorker).not_to receive(:perform_async)
       count_before = count_scheduled
 
-      expect { service.execute }.to raise_error(StandardError)
+      expect { service.execute(application) }.to raise_error(StandardError)
       expect(count_scheduled).to eq(count_before)
     end
   end
 
   describe '#execute' do
-    let(:application_class) { Clusters::Applications::Helm }
-    let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
-    let(:project) { cluster.project }
-    let(:service) { described_class.new(project, nil, cluster: cluster, application_class: application_class) }
+    let(:project) { double(:project) }
+    let(:service) { described_class.new(project, nil) }
 
-    it 'creates a new application' do
-      allow(ClusterInstallAppWorker).to receive(:perform_async)
+    context 'when application is installable' do
+      let(:application) { create(:clusters_applications_helm, :installable) }
 
-      expect { service.execute }.to change { application_class.count }.by(1)
-    end
-
-    it 'make the application scheduled' do
-      expect(ClusterInstallAppWorker).to receive(:perform_async).with(application_class.application_name, kind_of(Numeric)).once
+      it 'make the application scheduled' do
+        expect(ClusterInstallAppWorker).to receive(:perform_async).with(application.name, kind_of(Numeric)).once
 
-      expect { service.execute }.to change { application_class.with_status(:scheduled).count }.by(1)
+        expect { service.execute(application) }.to change { application.class.with_status(:scheduled).count }.by(1)
+      end
     end
 
     context 'when installation is already in progress' do
       let(:application) { create(:clusters_applications_helm, :installing) }
-      let(:cluster) { application.cluster }
 
       it_behaves_like 'a failing service'
     end
 
-    context 'when application_class is nil' do
-      let(:application_class) { nil }
+    context 'when application is nil' do
+      let(:application) { nil }
 
       it_behaves_like 'a failing service'
     end
 
     context 'when application cannot be persisted' do
+      let(:application) { create(:clusters_applications_helm) }
+
       before do
-        expect_any_instance_of(application_class).to receive(:make_scheduled!).once.and_raise(ActiveRecord::RecordInvalid)
+        expect(application).to receive(:make_scheduled!).once.and_raise(ActiveRecord::RecordInvalid)
       end
 
       it_behaves_like 'a failing service'