code_coverage.rb

#!/usr/bin/env ruby

require 'yaml'

def find_value_for_key(yaml_file, key)
  yaml_file.each do |yaml_key, yaml_value|
    if key == yaml_key
      return yaml_value
    end
  end
  
  return nil
end

if ARGV.length != 1
  puts "Usage: #{$PROGRAM_NAME} derived_data_path"
  exit 1
end

slather_file = '.slather.yml'

# Open the slather yaml
slather_yml = YAML.load_file(File.join(Dir.pwd, slather_file))

# Get the scheme name
scheme_name = find_value_for_key(slather_yml, 'scheme')

if scheme_name == nil
  puts "Couldn't find scheme in #{slather_file}"
end

# Find the Scheme build artifact folder in DerivedData
derived_data_path = ARGV[0]
build_artifact_folder = ""
Dir.chdir(derived_data_path) do
  composed_regex = "^" + scheme_name + "-.*$"
  
  puts "Searching for build artifact folder using regex: #{composed_regex}"
  
  Dir.glob("*") do |file_name|
    if file_name =~ /#{composed_regex}/
      puts "Found " + file_name
      build_artifact_folder = file_name
      break
    end
  end
end

app_path = File.join(derived_data_path, build_artifact_folder, "Build/Intermediates/CodeCoverage/Products/Debug-iphonesimulator/#{scheme_name}.framework/#{scheme_name}")
puts "Running slather with app path: #{app_path}"

system('slather', 'coverage', '--input-format', 'profdata', '-s', '--build-directory', derived_data_path, '--binary-file', app_path)