Use `:empty_project` where possible in serializer specs

spec/serializers/analytics_issue_serializer_spec.rb

@@ -8,7 +8,7 @@ describe AnalyticsIssueSerializer do
   end
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let(:project) { create(:empty_project) }
   let(:resource) do
     {
       total_time: "172802.724419",

spec/serializers/analytics_merge_request_serializer_spec.rb

@@ -8,7 +8,7 @@ describe AnalyticsMergeRequestSerializer do
   end
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let(:project) { create(:empty_project) }
   let(:resource) do
     {
       total_time: "172802.724419",

spec/serializers/commit_entity_spec.rb

@@ -6,7 +6,7 @@ describe CommitEntity do
   end
   let(:request) { double('request') }
-  let(:project) { create(:project) }
+  let(:project) { create(:project, :repository) }
   let(:commit) { project.commit }
   subject { entity.as_json }

spec/serializers/environment_serializer_spec.rb

@@ -2,7 +2,7 @@ require 'spec_helper'
 describe EnvironmentSerializer do
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let(:project) { create(:empty_project) }
   let(:json) do
     described_class
@@ -11,21 +11,20 @@ describe EnvironmentSerializer do
   end
   context 'when there is a single object provided' do
-    before do
-      create(:ci_build, :manual, name: 'manual1',
-                                 pipeline: deployable.pipeline)
-    end
-
+    let(:project) { create(:project, :repository) }
+    let(:deployable) { create(:ci_build) }
     let(:deployment) do
       create(:deployment, deployable: deployable,
                           user: user,
                           project: project,
                           sha: project.commit.id)
     end
-
-    let(:deployable) { create(:ci_build) }
     let(:resource) { deployment.environment }
+    before do
+      create(:ci_build, :manual, name: 'manual1', pipeline: deployable.pipeline)
+    end
+
     it 'contains important elements of environment' do
       expect(json)
         .to include(:name, :external_url, :environment_path, :last_deployment)