zsh function to show specs to code ratio in a rails folder, anything over 0.75 is good.

gistfile1.txt

prompt_rspec_stats() {
  if [[ ((-d app || -d lib) && -d spec) ]]; then
    if [[ (-d app) ]]; then
      local app=`wc -l app/**/*.rb | grep -oE "[0-9]+" | tail -n 1`
    else
      local app=`wc -l lib/**/*.rb | grep -oE "[0-9]+" | tail -n 1`
    fi

    local spec=$((`wc -l spec/**/*.rb | grep -oE "[0-9]+" | tail -n 1`))+0.01
    local ratio=`printf "%.2f\n" $((spec/app))`

    [[ ratio -ge 0.75 ]] && prompt_segment cyan black "$ratio"
    [[ ratio -ge 0.5 && ratio -lt 0.75 ]] && prompt_segment yellow black "$ratio"
    [[ ratio -lt 0.5 ]] && prompt_segment red black "$ratio"
  fi
}

Nice piece of code! Just ported it to powerlevel9k-Theme:
Powerlevel9k/powerlevel9k#19