What I expected to happen was...:
Villagers would be able to use double doors and fence gates.
What actually happened was...:
They can't. They use just one door and the fence gate is completely unrecognised and they cannot open or close it. They try to get in the house but they can't go through. As for the twin doors they just focus on one and ignore the second.
Steps to Reproduce:
1. Make a big house.
2. Add double doors
3. Add a fence and a fence gate around the house.
4. Add some villagers in the house, in the garden and outside of the house
5. /time set night
This is a feature request for Minecraft.
Right now, villagers are only able to open doors, not fencegates.
If you want to suggest features, you can do it over at the Minecraft Forums