Save this in your project root and launch with the watchr gem `watchr phpunit.watchr`. This will now watch every test file for all bundles in src for changes and if a change is found it will run `phpunit -c app changedfile`

gistfile1.txt

$ gem install watchr
$ cd /path/to/symfony-project
$ wget https://raw.github.com/gist/1151531/f12b125fed843086c05377d4f76185797121cbc6/phpunit.watchr
$ watchr phpunit.watchr

phpunit.watchr

# Copyright (C) 2011 by Henrik Bjornskov <henrik@bjrnskov.dk>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

watch '^src/.*.php' do |match|
    # If match[0] ends in Test.php lets assume it is a test file and done do the 
    # replacement magic

    test = match[0]

    unless test.end_with?('Test.php')
        test = test.sub(/^((.*)Bundle(\/))/, "\\1Tests/").sub(/\.php$/, "Test.php")
    end

    if File.exists?(test)
        system "phpunit -c app #{test}"
    else
        puts "'#{test}' does not exists."
    end
end