return value is correctly encoded as a n Address

precompile/living-assets/src/lib.rs

@@ -5,7 +5,8 @@ use fp_evm::{ExitError, Precompile, PrecompileFailure, PrecompileHandle, Precomp
 use pallet_living_assets_ownership::{traits::CollectionManager, CollectionId};
 use parity_scale_codec::Encode;
 use precompile_utils::{
-	keccak256, succeed, EvmResult, FunctionModifier, LogExt, LogsBuilder, PrecompileHandleExt,
+	keccak256, succeed, Address, EvmDataWriter, EvmResult, FunctionModifier, LogExt, LogsBuilder,
+	PrecompileHandleExt,
 };
 use sp_runtime::SaturatedConversion;
 
@@ -60,7 +61,7 @@ where
 							.log2(SELECTOR_LOG_CREATE_COLLECTION, collection_address, Vec::new())
 							.record(handle)?;
 
-						Ok(succeed(collection_address.encode()))
+						Ok(succeed(EvmDataWriter::new().write(Address(collection_address)).build()))
 					},
 					Err(err) => Err(PrecompileFailure::Error {
 						exit_status: ExitError::Other(sp_std::borrow::Cow::Borrowed(err)),

precompile/living-assets/src/tests.rs

@@ -6,7 +6,7 @@
 use super::*;
 use evm::ExitRevert;
 use helpers::*;
-use sp_core::{H160, H256};
+use sp_core::H160;
 use sp_std::vec::Vec;
 
 type CollectionId = u64;
@@ -60,14 +60,14 @@ fn create_collection_should_return_address() {
 	assert!(result.is_ok());
 	// check that the output is the collection id 0
 	assert_eq!(
-		result.unwrap().output,
-		hex::decode("8000000000000000000000000000000000000005").unwrap()
+		hex::encode(result.unwrap().output),
+		"0000000000000000000000008000000000000000000000000000000000000005"
 	);
 }
 
 #[test]
 fn create_collection_should_generate_log() {
-	impl_precompile_mock_simple!(Mock, Ok(5), Some(H160::zero()));
+	impl_precompile_mock_simple!(Mock, Ok(0xffff), Some(H160::zero()));
 
 	let mut handle = create_mock_handle_from_input(CREATE_COLLECTION);
 	let result = Mock::execute(&mut handle);
@@ -78,11 +78,8 @@ fn create_collection_should_generate_log() {
 	assert_eq!(logs[0].topics.len(), 2);
 	assert_eq!(logs[0].topics[0], SELECTOR_LOG_CREATE_COLLECTION.into());
 	assert_eq!(
-		logs[0].topics[1],
-		H256::from_slice(
-			&hex::decode("0000000000000000000000008000000000000000000000000000000000000005")
-				.unwrap()
-		)
+		hex::encode(logs[0].topics[1]),
+		"000000000000000000000000800000000000000000000000000000000000ffff"
 	);
 	assert_eq!(logs[0].data, Vec::<u8>::new());
 }