[stable2407] Backport #7013 (#7015)

Backport #7013 into `stable2407` from bkchr.

See the
[documentation](https://github.com/paritytech/polkadot-sdk/blob/master/docs/BACKPORT.md)
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---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: EgorPopelyaev <egor@parity.io>

prdoc/pr_7013.prdoc

+title: 'pallet-bounties: Fix benchmarks for 0 ED'
+doc:
+- audience: Runtime Dev
+  description: 'Closes: https://github.com/paritytech/polkadot-sdk/issues/7009'
+crates:
+- name: pallet-bounties
+  bump: patch

substrate/frame/bounties/src/benchmarking.rs

@@ -15,9 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! bounties pallet benchmarking.
-
-#![cfg(feature = "runtime-benchmarks")]
+//! Bounties pallet benchmarking.
 
 use super::*;
 
@@ -33,6 +31,16 @@ use pallet_treasury::Pallet as Treasury;
 
 const SEED: u32 = 0;
 
+fn minimum_balance<T: Config<I>, I: 'static>() -> BalanceOf<T, I> {
+	let minimum_balance = T::Currency::minimum_balance();
+
+	if minimum_balance.is_zero() {
+		1u32.into()
+	} else {
+		minimum_balance
+	}
+}
+
 // Create bounties that are approved for use in `on_initialize`.
 fn create_approved_bounties<T: Config<I>, I: 'static>(n: u32) -> Result<(), BenchmarkError> {
 	for i in 0..n {
@@ -58,12 +66,10 @@ fn setup_bounty<T: Config<I>, I: 'static>(
 	let fee = value / 2u32.into();
 	let deposit = T::BountyDepositBase::get() +
 		T::DataDepositPerByte::get() * T::MaximumReasonLength::get().into();
-	let _ = T::Currency::make_free_balance_be(&caller, deposit + T::Currency::minimum_balance());
+	let _ = T::Currency::make_free_balance_be(&caller, deposit + minimum_balance::<T, I>());
 	let curator = account("curator", u, SEED);
-	let _ = T::Currency::make_free_balance_be(
-		&curator,
-		fee / 2u32.into() + T::Currency::minimum_balance(),
-	);
+	let _ =
+		T::Currency::make_free_balance_be(&curator, fee / 2u32.into() + minimum_balance::<T, I>());
 	let reason = vec![0; d as usize];
 	(caller, curator, fee, value, reason)
 }
@@ -86,7 +92,7 @@ fn create_bounty<T: Config<I>, I: 'static>(
 
 fn setup_pot_account<T: Config<I>, I: 'static>() {
 	let pot_account = Bounties::<T, I>::account_id();
-	let value = T::Currency::minimum_balance().saturating_mul(1_000_000_000u32.into());
+	let value = minimum_balance::<T, I>().saturating_mul(1_000_000_000u32.into());
 	let _ = T::Currency::make_free_balance_be(&pot_account, value);
 }
 

substrate/frame/bounties/src/lib.rs

@@ -82,6 +82,7 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(feature = "runtime-benchmarks")]
 mod benchmarking;
 pub mod migrations;
 mod tests;