merge simplecov results

simplecov_merge.rb

require 'json'
require 'simplecov'     

Dir["coverage/.resultset-*.json"]
  .map(&File.method(:read))
  .map(&JSON.method(:parse))
  .map { |json| SimpleCov::Result.new(json['RSpec']['coverage']) }
  .then { |results| SimpleCov::ResultMerger.merge_results(*results) }
  .then { |merged_result| merged_result.covered_percent < 100 }

# or, ruby 2.6 proc composition style

json_to_simplecov_result = -> (json) { SimpleCov::Result.new(json['RSpec']['coverage']) }
transform_result_json = File.method(:read) >> JSON.method(:parse) >> json_to_simplecov_result

Dir["coverage/.resultset-*.json"]
  .map(&transform_result_json)
  .then { |results| SimpleCov::ResultMerger.merge_results(*results) }
  .then { |merged_result| merged_result.covered_percent < 100 }