Adds PipelineDestroy mutation

* Adds first spec

app/graphql/mutations/ci/base.rb

@@ -14,6 +14,7 @@ module Mutations
             description: 'The pipeline after mutation'
 
       authorize :update_pipeline
+      authorize :destroy_pipeline
 
       private
 

app/graphql/mutations/ci/pipeline_destroy.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Ci
+    class PipelineDestroy < Base
+      graphql_name 'PipelineDestroy'
+
+      def resolve(id:)
+        pipeline = authorized_find!(id: id)
+        project = pipeline.project
+
+        ::Ci::DestroyPipelineService.new(project, current_user).execute(pipeline)
+        {
+          errors: []
+        }
+      end
+
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -63,6 +63,7 @@ module Types
     mount_mutation Mutations::DesignManagement::Move
     mount_mutation Mutations::ContainerExpirationPolicies::Update
     mount_mutation Mutations::Ci::PipelineRetry
+    mount_mutation Mutations::Ci::PipelineDestroy
   end
 end
 

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

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'PipelineDestroy' do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let(:pipeline) { create(:ci_pipeline, :success, project: project, user: user) }
+
+  let(:mutation) do
+    variables = {
+      id: pipeline.id
+    }
+    graphql_mutation(:pipeline_destroy, variables,
+                     <<-QL
+                       errors
+                     QL
+    )
+  end
+
+  let(:mutation_response) { graphql_mutation_response(:pipeline_destroy) }
+
+  before do
+    project.add_maintainer(user)
+  end
+
+  it 'returns an error if the user is not allowed to destroy the pipeline' do
+    post_graphql_mutation(mutation, current_user: create(:user))
+
+    expect(graphql_errors).not_to be_empty
+  end
+
+  it 'retries a pipeline' do
+    post_graphql_mutation(mutation, current_user: user)
+
+    expect(response).to have_gitlab_http_status(:success)
+  end
+end