AP tests are only used for college credit and not considered in admission decisions. AP classes however show academic rigor which is considered by the UC’s and of course doing well in an AP class helps your GPA.
How your application is reviewed posted from UC Website:
We spend time evaluating your academic achievements in light of the opportunities available to you and your demonstrated capacity to contribute to the intellectual life at UC. The 14 factors we weigh are:
Academic grade point average in all completed “a-g” courses, including additional points for completed UC-certified honors courses.
Scores on the following tests: ACT with Writing or the SAT Reasoning Test.
Number of, content of and performance in academic courses beyond the minimum “a-g” requirements.
Number of and performance in UC-approved honors, Advanced Placement, International Baccalaureate Higher Level and transferable college courses.
Identification by UC as being ranked in the top 9 percent of your high school class at the end of your junior year (Eligible in the Local Context, or ELC).
Quality of your senior-year program as measured by the type and number of academic courses in progress or planned.
Quality of your academic performance relative to the educational opportunities available in your high school.
Outstanding performance in one or more specific subject areas.
Outstanding work in one or more special projects in any academic field of study.
Recent, marked improvement in academic performance as demonstrated by academic GPA and the quality of coursework completed or in progress.
Special talents, achievements and awards in a particular field, such as visual and performing arts, communication or athletic endeavors; special skills, such as demonstrated written and oral proficiency in other languages; special interests, such as intensive study and exploration of other cultures; experiences that demonstrate unusual promise for leadership, such as significant community service or significant participation in student government; or other significant experiences or achievements that demonstrate the student’s promise for contributing to the intellectual vitality of a campus.
Completion of special projects undertaken in the context of your high school curriculum or in conjunction with special school events, projects or programs.
Academic accomplishments in light of your life experiences and special circumstances, including but not limited to: disabilities, low family income, first generation to attend college, need to work, disadvantaged social or educational environment, difficult personal and family situations or circumstances, refugee status or veteran status.
Location of your secondary school and residence.