Custom RSpec formatter

failure_formatter.rb

# I don't like a lot of noise when my specs run.

# This will print the characters from 'progress', but clears the line every 10 so you don't get an epic line of dots.
#
# Any failures are printed as you go, so I can start looking while the the tests finish.
#
# You can simplify this with your .rspec-local file.
# rspec --require path/to/failure_formatter.rb -- format FailureFormatter spec

class FailureFormatter
  RSpec::Core::Formatters.register self, :example_passed, :example_failed, :dump_summary, :start_dump, :example_pending

  @@dot_count = 0
  N = 10 # how many dots before we clear the line?

  attr_reader :output

  def initialize(output)
    @output = output || StringIO.new
  end

  def example_passed(_notification)
    count_example('•', :success)
  end

  def example_pending(_notification)
    count_example('P', :pending)
  end

  def example_failed(notification)
    @@dot_count = 0
    clear_line

    output.puts RSpec::Core::Formatters::ConsoleCodes.wrap(notification.example.full_description, :failure)
    output.puts RSpec::Core::Formatters::ConsoleCodes.wrap(notification.example.location, :blue)

    if notification.example.exception.class == RSpec::Expectations::MultipleExpectationsNotMetError
      output.puts
      output.puts notification.example.exception.message
    else
      output.puts notification.example.exception
    end
    output.puts
  end

  def start_dump(_notification)
    clear_line
    output.puts
  end

  def dump_summary(summary)
    output.puts summary.colorized_totals_line
  end

  private

  def count_example(t, c)
    clear_line
    @@dot_count += 1
    output.print RSpec::Core::Formatters::ConsoleCodes.wrap(t * @@dot_count.modulo(N), c)
  end

  def clear_line
    output.print "\e[2K\r"
  end
end