Use autotest to run rails tests/specs impacted by changes shown by git-diff

gittest

#!/usr/bin/env ruby

require 'rubygems'
require 'autotest'
require 'optparse'

# exit if we're not in a git repository
exit $?.exitstatus unless system('git diff --name-only > /dev/null')

# make sure we're in the root path for the repository
loop do
  begin
    Dir.entries('.git')
    break
  rescue SystemCallError
    Dir.chdir('..')
    next   
  end
end

options = {:fast => false, :diff => 'HEAD', :trace => false}
OptionParser.new do |opts|
  opts.banner = "Usage: ./script/gittest [options]"
  opts.on("-f", "--fast", "Fast mode - skips preparation of test db") do |o|
    options[:fast] = o
  end
  opts.on("-d MANDATORY", "--diff MANDATORY", "Commit argument for git diff command used to check for new or modified files (defaults to HEAD)") do |o|
    options[:diff] = o
  end
  opts.on("-t", "--trace", "Enable trace option when calling rake tasks to prepare test db") do |o|
    options[:trace] = o
  end  
end.parse!

# prepare db if fast start not switched on
unless options[:fast]

  puts "Preparing test database..."
  puts "(You can use the -f switch to skip this in future)"
  rake_options = options[:trace] ? '--trace' : ''
  system "rake db:migrate RAILS_ENV=test #{$rake_options} > /dev/null"
  system "rake db:test:prepare #{$rake_options} > /dev/null"
 
end
      
# autotest options
$f = true # never run the entire test/spec suite on startup
$v = false
$h = false
$q = false
$DEBUG = false
$help = false

# use ansi colors to highlight test/spec passes, failures and errors
COLORS = { :red => 31, :green => 32, :yellow => 33 }

# get a list of new or modified files according to git (using terminal commands is faster than using a ruby git library)
new_or_modified_files = `git diff --name-only #{options[:diff]}`.split("\n").uniq

if new_or_modified_files.size == 0
  puts "No modified files, exiting"
  exit
end
  
msg = "#{new_or_modified_files.size} new or modified file" 
msg << "s" unless new_or_modified_files.size == 1
puts msg + ":"

new_or_modified_files.each {|f| puts "\t#{f}"}

at = Autotest.new
# Note: the initialize hook is normally called within Autotest#run
at.hook :initialize
at.reset
at.find_files # must populate the known files for autotest, otherwise Autotest#files_matching will always return nil

# this isn't pretty, but it will probably be reliable enough (can't see any good reason for renaming that particular instance variable, IMO it should be accessible anyway)
test_mappings = at.instance_eval { @test_mappings }

# find files to test
files_to_test = at.new_hash_of_arrays
new_or_modified_files.each do |f|
  next if f =~ at.exceptions # skip exceptions
  result = test_mappings.find { |file_re, ignored| f =~ file_re }
  unless result.nil?
    [result.last.call(f, $~)].flatten.each {|match| files_to_test[match] if File.exist?(match)}
  end
end

# exit if no files to test
puts "No matching files to test, exiting" and exit if files_to_test.empty?
  
msg = "#{files_to_test.size} file" 
msg << "s" unless files_to_test.size == 1
msg << " to test"
puts msg + ":"
puts "\t" + files_to_test.map{|k,v| k}.sort.join("\n\t")

puts "Press ENTER to continue, or CTRL+C to quit"
begin
  $stdin.gets # note: Kernel#gets assumes that ARGV contains a list of files from which to read next line
rescue Interrupt
  exit 1
end
puts "Running tests and specs, please wait..." 

cmd = at.make_test_cmd(files_to_test)

at.hook :run_command

# copied from Autotest#run_tests and updated to use ansi colours in TURN enabled test output and specs run with the format option set to specdoc
old_sync = $stdout.sync
$stdout.sync = true
results = []
line = []
begin
  open("| #{cmd}", "r") do |f|
    until f.eof? do
      c = f.getc or break
      # putc c
      line << c
      if c == ?\n then
        str = if RUBY_VERSION >= "1.9" then
                          line.join
                        else
                          line.pack "c*"
                        end
        results << str
        line.clear
        if str.match(/(PASS|FAIL|ERROR)$/)
          # test output
          case $1
            when 'PASS' ; color = :green
            when 'FAIL' ; color = :red
            when 'ERROR' ; color = :yellow
          end
          print "\e[#{COLORS[color]}m" + str + "\e[0m"
        elsif str.match(/^\- /)
          # spec output 
          if str.match(/^\- .*(ERROR|FAILED) \- [0-9]+/)
            color = $1 == 'FAILED' ? :red : :yellow 
            print "\e[#{COLORS[color]}m" + str + "\e[0m"
          else
            print "\e[#{COLORS[:green]}m" + str + "\e[0m"
          end
        else
          print str
        end
      end
    end
  end
ensure
  $stdout.sync = old_sync
end

at.handle_results(results.join)