Mock relay block number in dev service. (#453)

node/service/src/inherents.rs

@@ -79,7 +79,21 @@ use cumulus_test_relay_sproof_builder::RelayStateSproofBuilder;
 ///
 /// This is useful when running a node that is not actually backed by any relay chain.
 /// For example when running a local node, or running integration tests.
-pub struct MockValidationDataInherentDataProvider;
+///
+/// We mock a relay chain block number as follows:
+/// relay_block_number = offset + relay_blocks_per_para_block * current_para_block
+/// To simulate a parachain that starts in relay block 1000 and gets a block in every other relay
+/// block, use 1000 and 2
+pub struct MockValidationDataInherentDataProvider {
+	/// The current block number of the local block chain (the parachain)
+	pub current_para_block: u32,
+	/// The relay block in which this parachain appeared to start. This will be the relay block
+	/// number in para block #P1
+	pub relay_offset: u32,
+	/// The number of relay blocks that elapses between each parablock. Probably set this to 1 or 2
+	/// to simulate optimistic or realistic relay chain behavior.
+	pub relay_blocks_per_para_block: u32,
+}
 
 #[async_trait::async_trait]
 impl InherentDataProvider for MockValidationDataInherentDataProvider {
@@ -91,11 +105,15 @@ impl InherentDataProvider for MockValidationDataInherentDataProvider {
 		let (relay_storage_root, proof) =
 			RelayStateSproofBuilder::default().into_state_root_and_proof();
 
+		// Calculate the mocked relay block based on the current para block
+		let relay_parent_number =
+			self.relay_offset + self.relay_blocks_per_para_block * self.current_para_block;
+
 		let data = ParachainInherentData {
 			validation_data: PersistedValidationData {
 				parent_head: Default::default(),
 				relay_parent_storage_root: relay_storage_root,
-				relay_parent_number: Default::default(),
+				relay_parent_number,
 				max_pov_size: Default::default(),
 			},
 			downward_messages: Default::default(),

node/service/src/lib.rs

@@ -61,6 +61,7 @@ use sc_service::{
 	TFullClient, TaskManager,
 };
 use sp_api::ConstructRuntimeApi;
+use sp_blockchain::HeaderBackend;
 use std::sync::Arc;
 
 pub use client::*;
@@ -851,6 +852,8 @@ pub fn new_dev(
 				Therefore, a `LongestChainRule` is present. qed.",
 		);
 
+		let client_set_aside_for_cidp = client.clone();
+
 		task_manager.spawn_essential_handle().spawn_blocking(
 			"authorship_task",
 			run_manual_seal(ManualSealParams {
@@ -861,17 +864,28 @@ pub fn new_dev(
 				commands_stream,
 				select_chain,
 				consensus_data_provider: None,
-				create_inherent_data_providers: move |_, _| async move {
-					let time = sp_timestamp::InherentDataProvider::from_system_time();
-
-					let mocked_parachain = inherents::MockValidationDataInherentDataProvider;
-
-					//TODO I want to use the value from a variable above.
-					let author = nimbus_primitives::InherentDataProvider::<NimbusId>(
-						chain_spec::get_from_seed::<NimbusId>("Alice"),
-					);
-
-					Ok((time, mocked_parachain, author))
+				create_inherent_data_providers: move |block: H256, ()| {
+					let current_para_block = client_set_aside_for_cidp
+						.number(block)
+						.expect("Header lookup should succeed")
+						.expect("Header passed in as parent should be present in backend.");
+
+					async move {
+						let time = sp_timestamp::InherentDataProvider::from_system_time();
+
+						let mocked_parachain = inherents::MockValidationDataInherentDataProvider {
+							current_para_block,
+							relay_offset: 1000,
+							relay_blocks_per_para_block: 2,
+						};
+
+						//TODO I want to use the value from a variable above.
+						let author = nimbus_primitives::InherentDataProvider::<NimbusId>(
+							chain_spec::get_from_seed::<NimbusId>("Alice"),
+						);
+
+						Ok((time, mocked_parachain, author))
+					}
 				},
 			}),
 		);