fix tests

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -
I'm not sure why that wouldn't work, the should registered [here](https://github.com/symfony-cmf/Testing/blob/master/resources/config/dist/phpcr_odm.php#L39). Maybe you could try debugging that to see what is happening?