Fighting a warrior looks almost identical to that described above with one exception. Instead of the Flay after the Psychic Scream, move back away from the warrior.  This helps burns the timer on your Psychic Scream.  It is exceptionally important to kite warriors.  If a warrior can close and stay with you, you are dead. Also, if the warrior has a shield, stick with instants while at close range.  Do not try to Blast the warrior while he is standing on top of you. If the warrior has a shield at the beginning of combat, when you Scream, move away from the Warrior and immediately pop your shield.  Also be cognizant of your life bar.  A mortal strike warrior can deal close to two thousand damage very quickly… therefore if you life falls near that point, drop out of shadow form and heal yourself.

Finally, an evil trick that can be played on a warrior is mind control.  If you feel the situation is getting out of hand, pop focused casting (if you have it) then mind control the warrior. Hold him until all of your timers run out, or have the warrior agro mobs.  Remember that Mind Control has a very short range, and when you leave it, you lose control of the warrior.
 

A good shadow priest should kill a warrior the majority of the time.