In my phpunit I have this configuration:

```
<php>
    <env name="ENVIRONMENT" value="test"/>
</php>

```

I worked under the false assumption that it always would set the environment variable to the value `test`. Yet when the system already has the variable set, then it prefers the already existing value.

```
$ export ENVIRONMENT=GNARF
$ phpunit -c test/phpunit.xml

```

So inside the tests the value of `env('ENVIRONMENT')` will be `"GNARF"` even though I expected `"test"`.

Is there a way to make phpunit to treat the `env` setting not as a default but rather as the definite value it should be using?

I also would like to avoid calling phpunit in a certain way just to get the right env variables. 

So while this works:

```
ENVIRONMENT="test";./vendor/bin/phpunit -c tests/phpunit.xml

```

I rather configure it inside the `phpunit.xml` file if possible.