Laravel 5.5 Tests RefreshDatabase -> This database driver does not support dropping all tables

Like the title says.

With Laravel 5.4 i ran my tests with 
```
use DatabaseMigrations;
```
without problems.

Now with Laravel 5.5 no matter if i use
```
use DatabaseMigrations;
```
or 
```
use RefreshDatabase
```

i get an exception when i run my tests:
```
LogicException: This database driver does not support dropping all tables.
```