Testing for bipolar disorder, what does it consist on?

Clinical Evaluation. There is no "test" for bipolar disorder. It is a clinical diagnosis that looks for a pattern of episodic mood changes, usually times of depression as well as times of mania. Each of these has specific symptoms that clinicians ask about relating to sleep, energy level, appetitie, and behaviors, along with mood. Family history also can be important.
No test. A good clinical interview about the longitudinal history of mood swings and ruling out any physical cause is the only way to identify bipolar disorder.