Adds pipeline cancel and refactors

* Refactors some spec variables

app/graphql/mutations/ci/pipeline_cancel.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Ci
+    class PipelineCancel < BaseMutation
+      graphql_name 'PipelineCancel'
+
+      authorize :update_pipeline
+
+      def resolve
+        ::Ci::CancelUserPipelinesService.new.execute(current_user)
+
+        {
+          errors: []
+        }
+      end
+
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -62,8 +62,9 @@ module Types
     mount_mutation Mutations::DesignManagement::Delete, calls_gitaly: true
     mount_mutation Mutations::DesignManagement::Move
     mount_mutation Mutations::ContainerExpirationPolicies::Update
-    mount_mutation Mutations::Ci::PipelineRetry
+    mount_mutation Mutations::Ci::PipelineCancel
     mount_mutation Mutations::Ci::PipelineDestroy
+    mount_mutation Mutations::Ci::PipelineRetry
   end
 end
 

spec/requests/api/graphql/mutations/ci/pipeline_cancel_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'PipelineCancel' do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let(:pipeline) { create(:ci_pipeline, :running, project: project, user: user) }
+
+  let(:mutation) do
+    graphql_mutation(:pipeline_cancel, {},
+      <<-QL
+        errors
+      QL
+    )
+  end
+
+  before do
+    project.add_maintainer(user)
+  end
+
+  it 'does not change any pipelines not owned by the current user' do
+    build = create(:ci_build, :running, pipeline: pipeline)
+
+    post_graphql_mutation(mutation, current_user: create(:user))
+
+    expect(build).not_to be_canceled
+  end
+
+  it "cancels all of the current user's cancelable pipelines" do
+    build = create(:ci_build, :running, pipeline: pipeline)
+
+    post_graphql_mutation(mutation, current_user: user)
+
+    expect(response).to have_gitlab_http_status(:success)
+    expect(build.reload).to be_canceled
+  end
+end

spec/requests/api/graphql/mutations/ci/pipeline_destroy_spec.rb

@@ -32,7 +32,7 @@ RSpec.describe 'PipelineDestroy' do
     expect(graphql_errors).not_to be_empty
   end
 
-  it 'retries a pipeline' do
+  it 'destroys a pipeline' do
     post_graphql_mutation(mutation, current_user: user)
 
     expect(response).to have_gitlab_http_status(:success)

spec/requests/api/graphql/mutations/ci/pipeline_retry_spec.rb

@@ -5,8 +5,8 @@ require 'spec_helper'
 RSpec.describe 'PipelineRetry' do
   include GraphqlHelpers
 
-  let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
   let(:pipeline) { create(:ci_pipeline,  project: project, user: user) }
 
   let(:mutation) do