Set balance below existential

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Messages return `TypeSpec` directly - #[1999](https://github.com/paritytech/ink/pull/1999)
 - Fail when decoding from storage and not all bytes consumed - [#1897](https://github.com/paritytech/ink/pull/1897)
 - [E2E] resolve DispatchError error details for dry-runs - [#1944](https://github.com/paritytech/ink/pull/1994)
+- [E2E] `set_account_balance` now can't set balance below existential deposit - [#1983](https://github.com/paritytech/ink/pull/1983)
 
 
 ## Version 5.0.0-alpha

crates/env/src/engine/off_chain/test_api.rs

@@ -27,6 +27,7 @@ use ink_engine::test_api::RecordedDebugMessages;
 use std::panic::UnwindSafe;
 
 pub use super::call_data::CallData;
+pub use ink_engine::ext::ChainSpec;
 pub use ink_engine::ChainExtension;
 
 /// Record for an emitted event.
@@ -45,15 +46,24 @@ pub struct EmittedEvent {
 /// Note that account could refer to either a user account or
 /// a smart contract account.
 ///
+/// If a 0 balance is set, this would not fail. This is useful for
+/// reaping an account.
+///
 /// # Errors
 ///
 /// - If `account` does not exist.
 /// - If the underlying `account` type does not match.
 /// - If the underlying `new_balance` type does not match.
+/// - If the `new_balance` is less than the existential minimum.
 pub fn set_account_balance<T>(account_id: T::AccountId, new_balance: T::Balance)
 where
     T: Environment<Balance = u128>, // Just temporary for the MVP!
 {
+    let min = ChainSpec::default().minimum_balance;
+    if new_balance < T::Balance::from(min) && new_balance != 0u128.into(){
+        panic!("Balance must be at least [{}]. Use 0 as balance to reap the account.", min);
+    }
+
     <EnvInstance as OnInstance>::on_instance(|instance| {
         instance
             .engine

crates/env/src/engine/off_chain/tests.rs

@@ -12,11 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{
-    engine::off_chain::impls::TopicsBuilder,
-    event::TopicsBuilderBackend,
-    Result,
-};
+use crate::{engine::off_chain::impls::TopicsBuilder,
+            event::TopicsBuilderBackend,
+            Result,
+            engine::off_chain::test_api::set_account_balance,
+            types::Environment,
+            DefaultEnvironment};
 
 #[test]
 fn topics_builder() -> Result<()> {
@@ -41,3 +42,28 @@ fn topics_builder() -> Result<()> {
         Ok(())
     })
 }
+#[test]
+fn test_set_account_balance() -> Result<()> {
+    pub use ink_engine::ext::ChainSpec;
+
+    crate::test::run_test::<DefaultEnvironment, _>(|_| {
+
+        let minimum_balance = ChainSpec::default().minimum_balance;
+
+        let result = std::panic::catch_unwind(|| {set_account_balance::<DefaultEnvironment>(
+            <DefaultEnvironment as Environment>::AccountId::from([0x1; 32]),
+            <DefaultEnvironment as Environment>::Balance::from(minimum_balance - 1))});
+
+        assert!(result.is_err());
+
+        set_account_balance::<DefaultEnvironment>(
+            <DefaultEnvironment as Environment>::AccountId::from([0x1; 32]),
+            <DefaultEnvironment as Environment>::Balance::from(0u128));
+
+        set_account_balance::<DefaultEnvironment>(
+            <DefaultEnvironment as Environment>::AccountId::from([0x1; 32]),
+            <DefaultEnvironment as Environment>::Balance::from(minimum_balance + 1));
+
+        Ok(())
+    })
+}