Does my buddy’s friendship level reset when I change buddy Pokémon?

For quite a while now, Pokémon GO has an improved buddy Pokémon system whereby you collect hearts by interacting with your buddy to unlock various friendship levels and additional perks.

Say I have Eevee as my buddy Pokémon and collect 30 hearts with it. Then I make Suicune my buddy. When I switch back to Eevee, will its buddy level be back to zero or will the progress have been kept?

Solution 1:

When you switch your buddies, the friendship level is maintained.

I just tested by switching out a buddy that had a "great" friendship level with another buddy and then switched back. The Pokemon kept it's great level friendship, along with all the hearts it obtained for the day and walking distance for candy