Intent or not intent, that is the question? If Bullock is found guilty, the trial proceeds to Phase 2 where the defense is in the hot seat

While there are other tests on insanity, a google search and most California  websites refer to the M'Naghten rule.

http://www.shouselaw.com/insanity.html

http://www.californiacriminald...

There are three other alternatives explained in the link below:  Irresistible Impulse Test, The Durham Test and  The ALI Test.

http://gov.uchastings.edu/public-law/docs/plri/tmpinsan.pdf

You can plead guilty and guilty by insanity. Bullock did not have to be sent away to be determined sane to participate in criminal proceedings. In such cases, all criminal proceedings are suspended until the defendant can participate in his or her own defense.

In Phase One, if the jury finds Gary Lee Bullock guilty, then a second phase of the trial will proceed to determine sanity and that can be determined by the same jury or the Judge. In Phase, the burden of the proof is on the defense to prove by a preponderance of evidence their case. It is not the same high standard of proof by reasonable doubt that the prosecution has to prove in any jury trial.

The links above explain in detail California law, defense on a guilty by insanity plea.

Bullock has entered both a plea of guilty, and guilty by insanity.