Fix spec because of missing project for validation

app/models/clusters/cluster.rb

@@ -94,7 +94,7 @@ module Clusters
     private
 
     def unique_environment_scope
-      if project.clusters.where(environment_scope: environment_scope).where.not(id: self.id).exists?
+      if project && project.clusters.where(environment_scope: environment_scope).where.not(id: self.id).exists?
         errors.add(:base, "cannot add duplicated environment scope")
         return false
       end

spec/factories/clusters/clusters.rb

@@ -4,7 +4,7 @@ FactoryBot.define do
     name 'test-cluster'
 
     trait :project do
-      after(:create) do |cluster, evaluator|
+      before(:create) do |cluster, evaluator|
         cluster.projects << create(:project)
       end
     end