What are tests for cerebral palsy diagnosis please?

No tests for CP. There are no tests specific for cerebral palsy. The diagnosis is made on clinical examination results. CAT scan or MRI is used to determine what happened to the brain. There are some blood tests for intrauterine infection that are used.
History! Cerebral palsy is the term reserved for non progressive neurological deficits usually related to birth injury or events around the time of birth, infections, obstetric or other injuries from intrauterine causes, high bilirubin from jaundice etc.