1) Surround a block with steps, slabs, etc

2) Water log the blocks

3) Spawn villager in the center

4) Observe it will not path over the blocks

Will not path over: Cow, pig, sheep, ocelot, cat, mooshroom, rabbit, horse, donkey, mule, panda, enderman, witch, evoker, villager, trader, ravager

Will path over: Chicken, wolf, polar bear, llama, skeleton horse, zombie horse, turtle, creeper, silverfish, skeleton, wither skeleton, stray, slime, spider, zombie, pigman, husk, drowned, cave spider, endermite, magma cube, vindicator, pillager