You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: trigger_matrix_spec.rb
    path of file: ./repos/gitlabhq/qa/qa/specs/features/browser_ui/4_verify/pipeline
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module QA
  RSpec.describe 'Verify', :runner, :reliable, product_group: :pipeline_authoring do
    describe 'Trigger matrix' do
      let(:executor) { "qa-runner-#{Faker:
    
      def child_ci_file
        {
          action: 'create',
          file_path: 'child.yml',
          content: <<~YAML
            test_vars:
              script:
                - echo $PROVIDER
                - echo $STACK
              tags: [#{executor}]
          YAML
        }
      end