PHPUnit test classes with camel case or underscore

When writing test cases inthe xUnit style that PHPUnit follows it seems that everyone follows the camel case convention for function names:

public function testObjectHasFluentInterface()
{
    // ...
}

I have been naming my methods with a more "eloquent" PHPSpec style:

public function test_it_has_a_fluent_interface()
{
    // ...
}

Will this style create problems for me in the future? Personally I find it vastly more readable and easy to come back to.