parachains.rs

			let payload = localized_payload(statement, parent_hash);
			let signature = key.sign(&payload[..]).into();

			candidate.validity_votes.push((idx as ValidatorIndex, if vote_implicit {
				ValidityAttestation::Implicit(signature)
			} else {
				ValidityAttestation::Explicit(signature)
			}));
		}
	}

	fn new_candidate_with_egress_roots(egress_queue_roots: Vec<(ParaId, H256)>) -> AttestedCandidate {
		AttestedCandidate {
			validity_votes: vec![],
			candidate: CandidateReceipt {
				parachain_index: 0.into(),
				collator: Default::default(),
				signature: Default::default(),
				head_data: HeadData(vec![1, 2, 3]),
				egress_queue_roots,
				fees: 0,
				block_data_hash: Default::default(),
				upward_messages: vec![],
			}
		}
	}

	fn new_candidate_with_upward_messages(
		id: u32,
		upward_messages: Vec<(ParachainDispatchOrigin, Vec<u8>)>
	) -> AttestedCandidate {
		AttestedCandidate {
			validity_votes: vec![],
			candidate: CandidateReceipt {
				parachain_index: id.into(),
				collator: Default::default(),
				signature: Default::default(),
				head_data: HeadData(vec![1, 2, 3]),
				egress_queue_roots: vec![],
				fees: 0,
				block_data_hash: Default::default(),
				upward_messages: upward_messages.into_iter()
					.map(|x| UpwardMessage { origin: x.0, data: x.1 })
					.collect(),
			}
		}
	}

	#[test]
	fn check_dispatch_upward_works() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
			(2u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains.clone()), || {
			let parachains = vec![0.into(), 1.into(), 2.into()];
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![0; 4] }
			]);
			Parachains::queue_upward_messages(1.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1; 4] }
			]);
			let mut dispatched: Vec<(ParaId, ParachainDispatchOrigin, Vec<u8>)> = vec![];
			let dummy = |id, origin, data: &[u8]| dispatched.push((id, origin, data.to_vec()));
			Parachains::dispatch_upward_messages(0, &parachains, 2, 3, dummy);
			assert_eq!(dispatched, vec![
				(0.into(), ParachainDispatchOrigin::Parachain, vec![0; 4])
			]);
			assert!(<RelayDispatchQueue>::get(ParaId::from(0)).is_empty());
			assert_eq!(<RelayDispatchQueue>::get(ParaId::from(1)).len(), 1);
		});
		with_externalities(&mut new_test_ext(parachains.clone()), || {
			let parachains = vec![0.into(), 1.into(), 2.into()];
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![0; 2] }
			]);
			Parachains::queue_upward_messages(1.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1; 2] }
			]);
			Parachains::queue_upward_messages(2.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![2] }
			]);
			let mut dispatched: Vec<(ParaId, ParachainDispatchOrigin, Vec<u8>)> = vec![];
			let dummy = |id, origin, data: &[u8]| dispatched.push((id, origin, data.to_vec()));
			Parachains::dispatch_upward_messages(0, &parachains, 2, 3, dummy);
			assert_eq!(dispatched, vec![
				(0.into(), ParachainDispatchOrigin::Parachain, vec![0; 2]),
				(2.into(), ParachainDispatchOrigin::Parachain, vec![2])
			]);
			assert!(<RelayDispatchQueue>::get(ParaId::from(0)).is_empty());
			assert_eq!(<RelayDispatchQueue>::get(ParaId::from(1)).len(), 1);
			assert!(<RelayDispatchQueue>::get(ParaId::from(2)).is_empty());
		});
		with_externalities(&mut new_test_ext(parachains.clone()), || {
			let parachains = vec![0.into(), 1.into(), 2.into()];
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![0; 2] }
			]);
			Parachains::queue_upward_messages(1.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1; 2] }
			]);
			Parachains::queue_upward_messages(2.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![2] }
			]);
			let mut dispatched: Vec<(ParaId, ParachainDispatchOrigin, Vec<u8>)> = vec![];
			let dummy = |id, origin, data: &[u8]| dispatched.push((id, origin, data.to_vec()));
			Parachains::dispatch_upward_messages(1, &parachains, 2, 3, dummy);
			assert_eq!(dispatched, vec![
				(1.into(), ParachainDispatchOrigin::Parachain, vec![1; 2]),
				(2.into(), ParachainDispatchOrigin::Parachain, vec![2])
			]);
			assert_eq!(<RelayDispatchQueue>::get(ParaId::from(0)).len(), 1);
			assert!(<RelayDispatchQueue>::get(ParaId::from(1)).is_empty());
			assert!(<RelayDispatchQueue>::get(ParaId::from(2)).is_empty());
		});
		with_externalities(&mut new_test_ext(parachains.clone()), || {
			let parachains = vec![0.into(), 1.into(), 2.into()];
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![0; 2] }
			]);
			Parachains::queue_upward_messages(1.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1; 2] }
			]);
			Parachains::queue_upward_messages(2.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![2] }
			]);
			let mut dispatched: Vec<(ParaId, ParachainDispatchOrigin, Vec<u8>)> = vec![];
			let dummy = |id, origin, data: &[u8]| dispatched.push((id, origin, data.to_vec()));
			Parachains::dispatch_upward_messages(2, &parachains, 2, 3, dummy);
			assert_eq!(dispatched, vec![
				(2.into(), ParachainDispatchOrigin::Parachain, vec![2]),
				(0.into(), ParachainDispatchOrigin::Parachain, vec![0; 2])
			]);
			assert!(<RelayDispatchQueue>::get(ParaId::from(0)).is_empty());
			assert_eq!(<RelayDispatchQueue>::get(ParaId::from(1)).len(), 1);
			assert!(<RelayDispatchQueue>::get(ParaId::from(2)).is_empty());
		});
	}

	#[test]
	fn check_queue_upward_messages_works() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] }
			];
			assert_ok!(Parachains::check_upward_messages(0.into(), &messages, 2, 3));

			// all good.
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
			]);
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1, 2] }
			];
			assert_ok!(Parachains::check_upward_messages(0.into(), &messages, 2, 3));
			Parachains::queue_upward_messages(0.into(), &messages);
			assert_eq!(<RelayDispatchQueue>::get(ParaId::from(0)), vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
				UpwardMessage { origin: ParachainDispatchOrigin::Parachain, data: vec![1, 2] },
			]);
		});
	}

	#[test]
	fn check_queue_full_upward_messages_fails() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			// oversize, but ok since it's just one and the queue is empty.
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0; 4] },
			];
			assert_ok!(Parachains::check_upward_messages(0.into(), &messages, 2, 3));

			// oversize and bad since it's not just one.
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0; 4] },
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);

			// too many messages.
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![1] },
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![2] },
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);
		});
	}

	#[test]
	fn check_queued_too_many_upward_messages_fails() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			// too many messages.
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
			]);
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![1] },
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![2] },
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);
		});
	}

	#[test]
	fn check_queued_total_oversize_upward_messages_fails() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			// too much data.
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0, 1] },
			]);
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![2, 3] },
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);
		});
	}

	#[test]
	fn check_queued_pre_jumbo_upward_messages_fails() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			// bad - already an oversize messages queued.
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0; 4] },
			]);
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] }
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);
		});
	}

	#[test]
	fn check_queued_post_jumbo_upward_messages_fails() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
		];
		with_externalities(&mut new_test_ext(parachains), || {
			// bad - oversized and already a message queued.
			Parachains::queue_upward_messages(0.into(), &vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0] },
			]);
			let messages = vec![
				UpwardMessage { origin: ParachainDispatchOrigin::Signed, data: vec![0; 4] }
			];
			assert_err!(
				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
				"Messages added when queue full"
			);
		});
	}

	#[test]
	fn upward_queuing_works() {
		// That the list of egress queue roots is in ascending order by `ParaId`.
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			// parachain 0 is self
			let mut candidates = vec![
				new_candidate_with_upward_messages(0, vec![
					(ParachainDispatchOrigin::Signed, vec![1]),
				]),
				new_candidate_with_upward_messages(1, vec![
					(ParachainDispatchOrigin::Parachain, vec![2]),
				])
			];
			candidates.iter_mut().for_each(make_attestations);

			assert_ok!(Parachains::dispatch(
				set_heads(candidates),
				Origin::NONE,
			));

			assert!(<RelayDispatchQueue>::get(ParaId::from(0)).is_empty());
			assert!(<RelayDispatchQueue>::get(ParaId::from(1)).is_empty());
		});
	}

	#[test]
	fn active_parachains_should_work() {
		let parachains = vec![
			(5u32.into(), vec![1,2,3], vec![1]),
			(100u32.into(), vec![4,5,6], vec![2]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			assert_eq!(Parachains::active_parachains(), vec![5u32.into(), 100u32.into()]);
			assert_eq!(Parachains::parachain_code(&5u32.into()), Some(vec![1,2,3]));
			assert_eq!(Parachains::parachain_code(&100u32.into()), Some(vec![4,5,6]));
		});
	}

	#[test]
	fn register_deregister() {
		let parachains = vec![
			(5u32.into(), vec![1,2,3], vec![1]),
			(100u32.into(), vec![4,5,6], vec![2,]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			assert_eq!(Parachains::active_parachains(), vec![5u32.into(), 100u32.into()]);

			assert_eq!(Parachains::parachain_code(&5u32.into()), Some(vec![1,2,3]));
			assert_eq!(Parachains::parachain_code(&100u32.into()), Some(vec![4,5,6]));

			assert_ok!(Parachains::register_parachain(99u32.into(), vec![7,8,9], vec![1, 1, 1]));

			assert_eq!(Parachains::active_parachains(), vec![5u32.into(), 99u32.into(), 100u32.into()]);
			assert_eq!(Parachains::parachain_code(&99u32.into()), Some(vec![7,8,9]));

			assert_ok!(Parachains::deregister_parachain(5u32.into()));

			assert_eq!(Parachains::active_parachains(), vec![99u32.into(), 100u32.into()]);
			assert_eq!(Parachains::parachain_code(&5u32.into()), None);
		});
	}

	#[test]
	fn duty_roster_works() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			let check_roster = |duty_roster: &DutyRoster| {
				assert_eq!(duty_roster.validator_duty.len(), 8);
				for i in (0..2).map(ParaId::from) {
					assert_eq!(duty_roster.validator_duty.iter().filter(|&&j| j == Chain::Parachain(i)).count(), 3);
				}
				assert_eq!(duty_roster.validator_duty.iter().filter(|&&j| j == Chain::Relay).count(), 2);
			};

			let duty_roster_0 = Parachains::calculate_duty_roster();
			check_roster(&duty_roster_0);

			System::initialize(&1, &H256::from([1; 32]), &Default::default(), &Default::default());
			let duty_roster_1 = Parachains::calculate_duty_roster();
			check_roster(&duty_roster_1);
			assert!(duty_roster_0 != duty_roster_1);


			System::initialize(&2, &H256::from([2; 32]), &Default::default(), &Default::default());
			let duty_roster_2 = Parachains::calculate_duty_roster();
			check_roster(&duty_roster_2);
			assert!(duty_roster_0 != duty_roster_2);
			assert!(duty_roster_1 != duty_roster_2);
		});
	}

	#[test]
	fn unattested_candidate_is_rejected() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			let candidate = AttestedCandidate {
				validity_votes: vec![],
				candidate: CandidateReceipt {
					parachain_index: 0.into(),
					collator: Default::default(),
					signature: Default::default(),
					head_data: HeadData(vec![1, 2, 3]),
					egress_queue_roots: vec![],
					fees: 0,
					block_data_hash: Default::default(),
					upward_messages: vec![],
				},

			};

			assert!(Parachains::dispatch(set_heads(vec![candidate]), Origin::NONE).is_err());
		})
	}

	#[test]
	fn attested_candidates_accepted_in_order() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			let mut candidate_a = AttestedCandidate {
				validity_votes: vec![],
				candidate: CandidateReceipt {
					parachain_index: 0.into(),
					collator: Default::default(),
					signature: Default::default(),
					head_data: HeadData(vec![1, 2, 3]),
					egress_queue_roots: vec![],
					fees: 0,
					block_data_hash: Default::default(),
					upward_messages: vec![],
				}
			};

			let mut candidate_b = AttestedCandidate {
				validity_votes: vec![],
				candidate: CandidateReceipt {
					parachain_index: 1.into(),
					collator: Default::default(),
					signature: Default::default(),
					head_data: HeadData(vec![2, 3, 4]),
					egress_queue_roots: vec![],
					fees: 0,
					block_data_hash: Default::default(),
					upward_messages: vec![],
				}
			};

			make_attestations(&mut candidate_a);
			make_attestations(&mut candidate_b);

			assert!(Parachains::dispatch(
				set_heads(vec![candidate_b.clone(), candidate_a.clone()]),
				Origin::NONE,
			).is_err());

			assert_ok!(Parachains::dispatch(
				set_heads(vec![candidate_a.clone(), candidate_b.clone()]),
				Origin::NONE,
			));
		});
	}

	#[test]
	fn duplicate_vote_is_rejected() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			let mut candidate = AttestedCandidate {
				validity_votes: vec![],
				candidate: CandidateReceipt {
					parachain_index: 0.into(),
					collator: Default::default(),
					signature: Default::default(),
					head_data: HeadData(vec![1, 2, 3]),
					egress_queue_roots: vec![],
					fees: 0,
					block_data_hash: Default::default(),
					upward_messages: vec![],
				}
			};

			make_attestations(&mut candidate);

			let mut double_validity = candidate.clone();
			double_validity.validity_votes.push(candidate.validity_votes[0].clone());

			assert!(Parachains::dispatch(
				set_heads(vec![double_validity]),
				Origin::NONE,
			).is_err());
		});
	}

	#[test]
	fn ingress_works() {
		use sr_primitives::traits::OnFinalize;

		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
			(99u32.into(), vec![1, 2, 3], vec![4, 5, 6]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			assert_eq!(Parachains::ingress(ParaId::from(1)), Some(Vec::new()));
			assert_eq!(Parachains::ingress(ParaId::from(99)), Some(Vec::new()));

			for i in 1..10 {
				System::set_block_number(i);

				let from_a = vec![(1.into(), [i as u8; 32].into())];
				let mut candidate_a = AttestedCandidate {
					validity_votes: vec![],
					candidate: CandidateReceipt {
						parachain_index: 0.into(),
						collator: Default::default(),
						signature: Default::default(),
						head_data: HeadData(vec![1, 2, 3]),
						egress_queue_roots: from_a.clone(),
						fees: 0,
						block_data_hash: Default::default(),
						upward_messages: vec![],
					}
				};

				let from_b = vec![(99.into(), [i as u8; 32].into())];
				let mut candidate_b = AttestedCandidate {
					validity_votes: vec![],
					candidate: CandidateReceipt {
						parachain_index: 1.into(),
						collator: Default::default(),
						signature: Default::default(),
						head_data: HeadData(vec![1, 2, 3]),
						egress_queue_roots: from_b.clone(),
						fees: 0,
						block_data_hash: Default::default(),
						upward_messages: vec![],
					}
				};

				make_attestations(&mut candidate_a);
				make_attestations(&mut candidate_b);

				assert_ok!(Parachains::dispatch(
					set_heads(vec![candidate_a, candidate_b]),
					Origin::NONE,
				));

				Parachains::on_finalize(i);
			}

			System::set_block_number(10);
			assert_ok!(Parachains::dispatch(
				set_heads(vec![]),
				Origin::NONE,
			));

			// parachain 1 has had a bunch of parachain candidates included,
			// which raises the watermark.
			assert_eq!(
				Parachains::ingress(ParaId::from(1)),
				Some(vec![
					(9, BlockIngressRoots(vec![
						(0.into(), [9; 32].into())
					]))
				]),
			);

			// parachain 99 hasn't had any candidates included, so the
			// ingress is piling up.
			assert_eq!(
				Parachains::ingress(ParaId::from(99)),
				Some((1..10).map(|i| (i, BlockIngressRoots(
					vec![(1.into(), [i as u8; 32].into())]
				))).collect::<Vec<_>>()),
			);

			assert_ok!(Parachains::deregister_parachain(1u32.into()));

			// after deregistering, there is no ingress to 1, but unrouted messages
			// from 1 stick around.
			assert_eq!(Parachains::ingress(ParaId::from(1)), None);
			assert_eq!(Parachains::ingress(ParaId::from(99)), Some((1..10).map(|i| (i, BlockIngressRoots(
				vec![(1.into(), [i as u8; 32].into())]
			))).collect::<Vec<_>>()));

			Parachains::on_finalize(10);
			System::set_block_number(11);

			let mut candidate_c = AttestedCandidate {
				validity_votes: vec![],
				candidate: CandidateReceipt {
					parachain_index: 99.into(),
					collator: Default::default(),
					signature: Default::default(),
					head_data: HeadData(vec![1, 2, 3]),
					egress_queue_roots: Vec::new(),
					fees: 0,
					block_data_hash: Default::default(),
					upward_messages: vec![],
				}
			};
			make_attestations(&mut candidate_c);

			assert_ok!(Parachains::dispatch(
				set_heads(vec![candidate_c]),
				Origin::NONE,
			));

			Parachains::on_finalize(11);
			System::set_block_number(12);

			// at the next block, ingress to 99 should be empty.
			assert_eq!(Parachains::ingress(ParaId::from(99)), Some(Vec::new()));
		});
	}

	#[test]
	fn egress_routed_to_non_existent_parachain_is_rejected() {
		// That no parachain is routed to which doesn't exist
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			// parachain 99 does not exist
			let non_existent = vec![(99.into(), [1; 32].into())];
			let mut candidate = new_candidate_with_egress_roots(non_existent);

			make_attestations(&mut candidate);

			let result = Parachains::dispatch(
				set_heads(vec![candidate.clone()]),
				Origin::NONE,
			);

			assert_eq!(Err("Routing to non-existent parachain"), result);
		});
	}

	#[test]
	fn egress_routed_to_self_is_rejected() {
		// That the parachain doesn't route to self
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			// parachain 0 is self
			let to_self = vec![(0.into(), [1; 32].into())];
			let mut candidate = new_candidate_with_egress_roots(to_self);

			make_attestations(&mut candidate);

			let result = Parachains::dispatch(
				set_heads(vec![candidate.clone()]),
				Origin::NONE,
			);

			assert_eq!(Err("Parachain routing to self"), result);
		});
	}

	#[test]
	fn egress_queue_roots_out_of_order_rejected() {
		// That the list of egress queue roots is in ascending order by `ParaId`.
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			// parachain 0 is self
			let out_of_order = vec![(1.into(), [1; 32].into()), ((0.into(), [1; 32].into()))];
			let mut candidate = new_candidate_with_egress_roots(out_of_order);

			make_attestations(&mut candidate);

			let result = Parachains::dispatch(
				set_heads(vec![candidate.clone()]),
				Origin::NONE,
			);

			assert_eq!(Err("Egress routes out of order by ID"), result);
		});
	}

	#[test]
	fn egress_queue_roots_empty_trie_roots_rejected() {
		let parachains = vec![
			(0u32.into(), vec![], vec![]),
			(1u32.into(), vec![], vec![]),
			(2u32.into(), vec![], vec![]),
		];

		with_externalities(&mut new_test_ext(parachains), || {
			// parachain 0 is self
			let contains_empty_trie_root = vec![(1.into(), [1; 32].into()), ((2.into(), EMPTY_TRIE_ROOT.into()))];
			let mut candidate = new_candidate_with_egress_roots(contains_empty_trie_root);

			make_attestations(&mut candidate);

			let result = Parachains::dispatch(
				set_heads(vec![candidate.clone()]),
				Origin::NONE,
			);

			assert_eq!(Err("Empty trie root included"), result);
		});
	}

	#[test]
	fn empty_trie_root_const_is_blake2_hashed_null_node() {
		let hashed_null_node =  <NodeCodec<Blake2Hasher> as trie_db::NodeCodec<Blake2Hasher>>::hashed_null_node();
		assert_eq!(hashed_null_node, EMPTY_TRIE_ROOT.into())
	}
}