I work as a loan officer for a wholesale mortgage bank in Austin, Texas. Our guidelines state that you must have a minimum two-year work history in the same line of work. If there is a job gap of more than 30 days within that two year history, you may have a difficult time getting approved for a loan. It may be possible if you have strong compensating factors to offset the lack of work history and/or job gap. For example, if you have a second source of reliable income or enough assets in the bank...along with a high FICO score; an underwriter may be able to offset the lack of work history.
Another item to note: If you were self-employed and are now a full-time employee, then you will have a better chance of receiving an approval for a loan. If it is the other way around (full-time employee switching to self-employed), then you can almost count on the fact that you will have to wait for 2 years to receive loan approval.
It is always a good idea to check with a few different lenders in your area. I am sure that California Lending Laws differ from Texas Lending Laws.