Uncontested elections still require a vote. This goes back to your by-laws. You must follow your by-laws.
Most by-laws state that Board Members are elected by the membership. If you don't have an opportunity for voting... even if it's uncontested... then you have not followed your by-laws.
This absolutely happens. When you hold an election with uncontested position(s), I highly suggest the ballot to look something like this:
President:
- Example Name1
Secretary
- Example Name2
- Example Name3
Then people select their chosen candidates. They are NOT provided with a "yes/no" option for uncontested positions, but do give voters the chance to not vote for someone. (meaning they can skip the question, and leave it blank, and still submit the rest of the ballot; this is useful if someone doesn't know the candidate)