Allow setting block time for off-chain testing

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Basic support for `dyn Trait` to allow cross-contract calls only with trait - [#1673](https://github.com/paritytech/ink/pull/1673)
 - E2E: auto detect contracts to be built - [#1691](https://github.com/paritytech/ink/pull/1691)
 - Add `set_code_hash` to `EnvAccess` - [#1698](https://github.com/paritytech/ink/pull/1698)
+- Add `set_block_timestamp` to off-chain test api `Engine` - [#1721](https://github.com/paritytech/ink/pull/1721)
 
 ## Version 4.0.1
 
@@ -1931,4 +1932,4 @@ impl Contract {
 
 This is useful if the `impl` block itself does not contain any ink! constructors or messages, but you
 still need to access some of the "magic" provided by ink!. In the example above, you would not have
-access to `emit_event` without `#[ink(impl)]`.
+access to `emit_event` without `#[ink(impl)]`.

crates/engine/src/exec_context.rs

@@ -64,6 +64,11 @@ impl ExecContext {
     pub fn reset(&mut self) {
         *self = Default::default();
     }
+
+    /// Set the block timestamp for the execution context.
+    pub fn set_block_timestamp(&mut self, block_timestamp: BlockTimestamp) {
+        self.block_timestamp = block_timestamp
+    }
 }
 
 #[cfg(test)]

crates/engine/src/test_api.rs

@@ -17,6 +17,7 @@ use crate::{
     types::{
         AccountId,
         Balance,
+        BlockTimestamp,
     },
     AccountError,
     Error,
@@ -257,6 +258,11 @@ impl Engine {
     pub fn set_value_transferred(&mut self, value: Balance) {
         self.exec_context.value_transferred = value;
     }
+
+    /// Set the block timestamp for the execution context.
+    pub fn set_block_timestamp(&mut self, new_block_timestamp: BlockTimestamp) {
+        self.exec_context.block_timestamp = new_block_timestamp;
+    }
 }
 
 #[cfg(test)]

crates/engine/src/tests.rs

@@ -272,3 +272,21 @@ fn ecdsa_recovery_with_secp256k1_crate() {
     // then
     assert_eq!(output, pubkey.serialize());
 }
+
+#[test]
+fn setting_getting_block_timestamp() {
+    // given
+    let mut engine = Engine::new();
+    let new_block_timestamp: u64 = 1000;
+    let output = &mut &mut get_buffer()[..];
+
+    // when
+    engine.advance_block();
+    engine.set_block_timestamp(new_block_timestamp);
+    engine.block_timestamp(output);
+
+    // then
+    let output = <u64 as scale::Decode>::decode(&mut &output[..16])
+        .expect("decoding value transferred failed");
+    assert_eq!(output, new_block_timestamp);
+}

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

@@ -240,6 +240,16 @@ where
     })
 }
 
+/// Sets the block timestamp for the next [`advance_block`] invocation.
+pub fn set_block_timestamp<T>(value: T::Timestamp)
+where
+    T: Environment<Timestamp = u64>,
+{
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        instance.engine.set_block_timestamp(value);
+    })
+}
+
 /// Runs the given closure test function with the default configuration
 /// for the off-chain environment.
 pub fn run_test<T, F>(f: F) -> Result<()>