Extract spec files which were changed from specified branch/commit

changed-specs

#!/usr/bin/env ruby

#
# Example usage
# - Test only changed model files & specs from master
#   $ bundle exec rspec $(script/changed-specs model master)
#

require "open3"
require "shellwords"

def detect_spec_file(file_name)
  spec_file = if %r(^app\/(.+)) =~ file_name
                "spec/#{$1}"
              elsif %r(^spec\/(.+)) =~ file_name
                file_name
              else
                nil
              end

  return "" unless spec_file && File.exist?(spec_file)

  spec_file
end

def git_diff_command(base_branch)
  "git --no-pager diff --name-only #{Shellwords.escape(base_branch)}"
end

def model_spec?(spec_name)
  !!(%r(^spec/models) =~ spec_name)
end

def controller_spec?(spec_name)
  !!(%r(^spec/controllers) =~ spec_name)
end

def lib_spec?(spec_name)
  !!(%r(^spec/lib) =~ spec_name)
end

def helper_spec?(spec_name)
  !!(%r(^spec/helpers) =~ spec_name)
end

def mailer_spec?(spec_name)
  !!(%r(^spec/mailers) =~ spec_name)
end

def concern_spec?(spec_name)
  !!(%r(^spec/concern) =~ spec_name)
end

def feature_spec?(spec_name)
  !!(%r(^spec/features) =~ spec_name)
end

def select_run_specs(spec_types, spec_files)
  return spec_files if spec_types.include?("all")

  spec_types.inject([]) do |result, spec_type|
    result << spec_files.select { |spec| self.send("#{spec_type}_spec?", spec) }
    result
  end.flatten.uniq
end


AVAILABLE_SPEC_TYPES = %w(all model controller lib helper mailer concern feature)
USAGE = <<-EOS
$ changed-specs <types = all> <base_branch = master>

Available spec types:
#{AVAILABLE_SPEC_TYPES.map { |type| "  #{type}" }.join("\n")}
EOS

spec_types = %w(all)
base_branch = "master"

case ARGV.length
when 2
  spec_types, base_branch = ARGV[0].split(","), ARGV[1]
when 1
  spec_types = ARGV[0].split(",")
when 0
else
  $stderr.puts USAGE
  exit 1
end

spec_types.each do |spec_type|
  unless AVAILABLE_SPEC_TYPES.include?(spec_type.downcase)
    $stderr.puts USAGE
    exit 1
  end
end

stdout, stderr, exit_code = *Open3.capture3(git_diff_command(base_branch))

unless exit_code.to_i.zero?
  $stderr.puts stderr
  exit exit_code.to_i
end

spec_files = stdout.lines.map { |line| detect_spec_file(line.strip) }.reject { |spec| spec == "" }
run_spec_files = select_run_specs(spec_types, spec_files)

puts run_spec_files.join(" ")