Who would win?

For example:
If someone were to send 3 units towards a target with the same 3 unit types as it's defense, who would win and why?

defender win.
don't know why

but often time when i attack or defense with 1 man spam, the defender always win.

Both would lose all units, but the defenders would win. But the defenders are defenseless

Ok, thankyou guys. That was helpful.

Defender would win because both sides are killed, thus, there are no forces to claim the defenseless colony/outpost/relic.

all units would die and the owner of the outpost would keep it. If its a base then im sure all units would die on both sides and the base should not be conquered because the defender don't lose his outpost to attacks like this so he should not be conquered.