Pallet assets improvements (#13543)

substrate/frame/assets/src/mock.rs

@@ -91,12 +91,44 @@ impl pallet_balances::Config for Test {
 
 pub struct AssetsCallbackHandle;
 impl AssetsCallback<AssetId, AccountId> for AssetsCallbackHandle {
-	fn created(_id: &AssetId, _owner: &AccountId) {
-		storage::set(b"asset_created", &().encode());
+	fn created(_id: &AssetId, _owner: &AccountId) -> Result<(), ()> {
+		if Self::should_err() {
+			Err(())
+		} else {
+			storage::set(Self::CREATED.as_bytes(), &().encode());
+			Ok(())
+		}
 	}
 
-	fn destroyed(_id: &AssetId) {
-		storage::set(b"asset_destroyed", &().encode());
+	fn destroyed(_id: &AssetId) -> Result<(), ()> {
+		if Self::should_err() {
+			Err(())
+		} else {
+			storage::set(Self::DESTROYED.as_bytes(), &().encode());
+			Ok(())
+		}
+	}
+}
+
+impl AssetsCallbackHandle {
+	pub const CREATED: &'static str = "asset_created";
+	pub const DESTROYED: &'static str = "asset_destroyed";
+
+	const RETURN_ERROR: &'static str = "return_error";
+
+	// Configures `Self` to return `Ok` when callbacks are invoked
+	pub fn set_return_ok() {
+		storage::clear(Self::RETURN_ERROR.as_bytes());
+	}
+
+	// Configures `Self` to return `Err` when callbacks are invoked
+	pub fn set_return_error() {
+		storage::set(Self::RETURN_ERROR.as_bytes(), &().encode());
+	}
+
+	// If `true`, callback should return `Err`, `Ok` otherwise.
+	fn should_err() -> bool {
+		storage::exists(Self::RETURN_ERROR.as_bytes())
 	}
 }