Rake task to detect untested routes

appmap.rake

# Sort by path, then by method
compare_routes = lambda do |a,b|
  compare = a[1] <=> b[1]
  compare = a[0] <=> b[0] if compare == 0
  compare
end

normalize_method = lambda do |method|
  method = method.upcase
  # For Rails, HEAD request is served by 'show' (GET)
  # Similarly, PUT request is served by 'update' (PATCH)
  method = 'GET' if method == 'HEAD'
  method = 'PATCH' if method == 'PUT'
  method = 'GET' unless %w[GET CONNECT DELETE HEAD PUT POST PATCH OPTIONS TRACE].member?(method)
  method
end

rails_routes = lambda do
  `rails routes`.split("\n")
    .map do |line| 
      tokens = line.split(/\s+/)
      path_index = tokens.index { |token| token[0] == '/' }
      next unless path_index

      method = normalize_method.(tokens[path_index-1])
      path = tokens[path_index]
      path.gsub!('(.:format)', '')
      path.gsub!(/:[^\/]+/) { |match| [ '{', match[1..-1], '}' ].join('') }
      [ method, path ]
    end
      .compact
      .sort(&compare_routes)
      .map { |route| route.join(' ') }
      .uniq
end

openapi_routes = lambda do
  # Assumes AppMap-generated OpenAPI in the file swagger/openapi.yaml
  paths = YAML.load(File.read('swagger/openapi.yaml'))['paths']
  path_names = paths.keys
  paths.map do |entry|
    path_name, data = entry
    methods = data.keys
    methods.map do |method|
      [ normalize_method.(method), path_name ]
    end
  end
    .flatten(1)
    .sort(&compare_routes)
    .map { |route| route.join(' ') }
    .uniq
end

namespace :appmap do
  desc "Use information from swagger/openapi.yaml (generated by AppMap openapi command), and config/untested_routes.txt (a whitelist of routes to ignore) to determine which API routes are untested"
  task :untested_routes do
    # Create this files as empty, if it doesn't exist.
    # To allow untested routes that won't print in the final report, add those routes to this file.
    untested_routes_whitelist = File.read('config/untested_routes.txt')
      .split("\n")
      .select { |line| line.length > 0 && line[0] != '#' }
      .map(&:strip)
    untested_routes = rails_routes.() - openapi_routes.() - untested_routes_whitelist
    undeclared_routes = openapi_routes.() - rails_routes.()

    unless untested_routes.empty?
      puts 'Untested routes'
      puts '---------------'
      puts untested_routes.join("\n")
    end
    unless undeclared_routes.empty?
      puts unless untested_routes.empty?
      puts 'Undeclared routes'
      puts '-----------------'
      puts undeclared_routes.join("\n")
    end
  end
end