Hi David, welcome to the forum! Children definitely test both in real life and in the consulting room. Their tests could be related to either developmental issues or to master traumatic situations and sometimes a situation contains both. A child might test to see if a parent would be hurt if they become more independent, act stronger or show great ambition. A child might worry that their needs are too great and test if they are a burden to their parents. A child who is exploring their sexual feelings might test to see if a parent was threatened by their sexual feelings. As a child is developing normally, different issues emerge naturally which are most significant to him or her. He or she would be likely to test around whatever issue is on their mind- whatever holds anxiety for them.
One of the ways that a child's test will be different from an adult's is in the fact that they are usually still at home and involved with their parents. They do not have the distance or luxury to test as vigorously as an adult who in reality could survive without their parents. Children need to get along with their parents so after some mild tests that fail they may adaptively postpone further testing till it is safe to do so. That might not be until they could leave home and survive on their own.
Does this fit with your experience? are you a child therapist? I was trained as a child therapist but mostly see adults now. SFPRG has made a movie on doing family and child treatment. You might enjoy seeing it. You could e-mail the group to get a copy (SFPSYCH@ wenet.com) What do other child therapists think?