class SimpleCov::Formatter::SimpleFormatter

def format(result)

Takes a SimpleCov::Result and generates a string out of it 
def format(result)
  output = "".dup
  result.groups.each do |name, files|
    output << "Group: #{name}\n"
    output << "=" * 40
    output << "\n"
    files.each do |file|
      output << "#{file.filename} (coverage: #{file.covered_percent.round(2)}%)\n"
    end
    output << "\n"
  end
  output
end