Reintroduce tests after removing them

In previous commits on this branch I've removed methods and their tests.
Now these methods where used by another branch so I needed to
reintroduce them.

app/controllers/projects/merge_requests_controller.rb

@@ -378,10 +378,12 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     if deployments
       deployments = deployments.map do |deployment|
+        project = deployment.project
+
         deployment = {
           environment_name: deployment.environment.name,
           environment_id: deployment.environment.id,
-          environment_url: namespace_project_environment_path(@project.namespace, @project, deployment.environment),
+          environment_url: namespace_project_environment_path(project.namespace, project, deployment.environment),
           external_url: deployment.environment.external_url,
           created_at: deployment.created_at,
           created_at_formatted: deployment.created_at.to_time.in_time_zone.to_s(:medium)

app/models/deployment.rb

@@ -33,6 +33,12 @@ class Deployment < ActiveRecord::Base
     project.repository.fetch_ref(project.repository.path_to_repo, ref, ref_path)
   end
+  def includes_commit?(commit)
+    return false unless commit
+
+    project.repository.is_ancestor?(commit.id, sha)
+  end
+
   def manual_actions
     deployable.try(:other_actions)
   end

app/models/environment.rb

@@ -38,6 +38,12 @@ class Environment < ActiveRecord::Base
       end
   end
+  def includes_commit?(commit)
+    return false unless last_deployment
+
+    last_deployment.includes_commit?(commit)
+  end
+
   def deployment_id_for(commit)
     ref = project.repository.ref_name_for_sha(ref_path, commit.sha)

spec/models/deployment_spec.rb

@@ -15,4 +15,28 @@ describe Deployment, models: true do
   it { is_expected.to validate_presence_of(:ref) }
   it { is_expected.to validate_presence_of(:sha) }
+
+  describe '#includes_commit?' do
+    let(:project)     { create(:project) }
+    let(:environment) { create(:environment, project: project) }
+    let(:deployment) do
+      create(:deployment, environment: environment, sha: project.commit.id)
+    end
+
+    context 'when there is no project commit' do
+      it 'returns false' do
+        commit = project.commit('feature')
+
+        expect(deployment.includes_commit?(commit)).to be false
+      end
+    end
+
+    context 'when they share the same tree branch' do
+      it 'returns true' do
+        commit = project.commit
+
+        expect(deployment.includes_commit?(commit)).to be true
+      end
+    end
+  end
 end

spec/models/environment_spec.rb

@@ -31,6 +31,39 @@ describe Environment, models: true do
     end
   end
+  describe '#includes_commit?' do
+    context 'without a last deployment' do
+      it "returns false" do
+        expect(environment.includes_commit?('HEAD')).to be false
+      end
+    end
+
+    context 'with a last deployment' do
+      let(:project)     { create(:project) }
+      let(:environment) { create(:environment, project: project) }
+
+      let!(:deployment) do
+        create(:deployment, environment: environment, sha: project.commit('master').id)
+      end
+
+      context 'in the same branch' do
+        it 'returns true' do
+          expect(environment.includes_commit?(RepoHelpers.sample_commit)).to be true
+        end
+      end
+
+      context 'not in the same branch' do
+        before do
+          deployment.update(sha: project.commit('feature').id)
+        end
+
+        it 'returns false' do
+          expect(environment.includes_commit?(RepoHelpers.sample_commit)).to be false
+        end
+      end
+    end
+  end
+
   describe '#deployment_id_for' do
     let(:project)       { create(:project) }
     let!(:environment)  { create(:environment, project: project) }