Can PHPUnit temporarily reset system paths before a run?

I'm using phpunit-spiderling alongside PHPUnit to run browser/functional tests on PhantomJS, installed via jonnyw/php-phantomjs, which in turn installs the phantomjs binary in <project>/bin. Since that folder is not in the system path, I need to start tests thus:

PATH=$PATH:`pwd`/bin ./phpunit test/browser/tests

This works fine, but I expect I'll need to condense it into the raw command when I set this up on hosted CI, without the environment prefix:

./phpunit test/browser/tests

I've tried a --bootstrap command to run a system() command to reset the system path, to no avail, and I can't see anything in the manual that describes how to do this via phpunit.xml. Unfortunately Spiderling hard-wires the Phantom command, and it is expected to be visible in the system path.

I've also tried doing this is a setUp() test method, but that's too late - Spiderling will already have tried, and failed, to start up PhantomJS on a random port.

(The command ./phpunit is just a symlink to vendor/phpunit/phpunit/phpunit, which is PHPUnit installed via Composer.)

Solution

Further to this question, it turns out that:

hosted CI tools offer ways of achieving this outside of PHPUnit
Travis, which I am using, offers phantomjs in the standard path anyway

Thus, whilst it turns out I don't need this, there seems to be two ways to achieve it. Since my approach requires the execution of the backticks, I wonder if the env approach might not work. However, for completeness, here is both:

The env approach is an entry in the .travis.yml file.
You could also try a before_script key with a value thus:
```
before_script:
  - export PATH=`pwd`/bin:$PATH
```
Since the working directory should be set to the root of the project, the pwd plus the subdirectory should add in the new path to the system path.