run lint and db:seed in specs only if changed

lint_spec.rb

# spec/lint_spec.rb

require "rails_helper"

RSpec.describe "Lint" do
  it "FactoryGirl" do
    should_run = directory_changed?("spec/factories")  || directory_changed?("db")
    next unless should_run

    FactoryGirl.lint
  end

  context "db seeds" do
    let(:command) { "bundle exec rake db:seed --trace" }

    it "runs rake db:seed succesfully" do
      next unless directory_changed?("db")

      result, success = invoke_rake_command!

      failure!(result) unless success

      cleanup_db!
    end

    def invoke_rake_command!
      puts "Running #{command}"

      result = `#{command} 2>&1`

      [result, $?]
    end

    def cleanup_db!
      puts "Command completed - cleaning db"

      DatabaseCleaner.clean_with :truncation
      DatabaseCleaner.clean
      puts "DB cleaned"
    end

    SeedExecutionFailure = Class.new StandardError

    def failure!
      message = ["-" * 80, "Failure executing command", command, result, "-" * 80].join("\n")
      raise SeedExecutionFailure.new message
    end
  end

  def directory_changed?(dir)
    return false
    result = `git diff master -- #{dir} | wc -c`
    result.chomp.strip.to_i > 0
  end
end