How are Friendly Challenges different from normal PVP battles?
Friendly Challenges are like practice battles. Anything that happens in a Friendly Challenge has no effect on your resources, troops, etc. 

-Food, Gold, Oil, and Trade Goods are not lost or gained. 

-Troops, tactics, and Generals are not lost.

-Generals active in the Castle will defend your base

-If you attack a base while under a Peace Treaty, you will still have one when you return. Likewise, you won’t gain a Peace Treaty for being defeated on defense. 

-Sprung traps will not need to be rearmed. 

-Medals are not lost or gained.

-Blessings are not used up.

-Teutonic Fury is not earned or lost.

-Victory Stars are not earned.

-Friendly Challenges do not appear in your Attack or Defense history.

Why can’t I choose a particular layout for an Friendly Challenge?
Layouts must be complete and valid to be used in Friendly Challenges. If your base has a red “!” next to it, you have more buildings that must be placed before you can use it.

Why can’t I do an Friendly Challenge twice?
To maintain a fair sense of competition, each Alliance member can only complete an Friendly Challenge once. If you want to try again, the challenge-maker can start a new challenge with the same base, but the results of the previous challenge will be lost. You can also issue and participate in your own Friendly Challenge.

Why did my Friendly Challenge disappear?
Friendly Challenges expire after 24 hours. If you want your Allies to challenge your base again, you can always start a new challenge with the same base layout. Challenges have a 10 minute cooldown to prevent players from spamming the chat, so you may have to wait a bit to challenge the same base again. Challenges remain active even if the challenger is offline.

Why don’t Coalitions appear in my Friendly Challenges?
Friendly Challenges currently assume you are making a regular attack, not a World War attack. Therefore, they always include Blessings and exclude Coalitions. You can still test out your War Base layouts in challenges - they just won’t include Coalitions.