paras.rs

			let new_code = ValidationCode(vec![4, 5, 6]);

			run_to_block(2, None);
			assert_eq!(Paras::current_code(&para_id), Some(vec![1, 2, 3].into()));

			let expected_at = {
				// this parablock is in the context of block 1.
				let expected_at = 1 + 5;
				Paras::schedule_code_upgrade(para_id, new_code.clone(), expected_at);
				Paras::note_new_head(para_id, Default::default(), 1);

				assert!(Paras::past_code_meta(&para_id).most_recent_change().is_none());
				assert_eq!(<Paras as Store>::FutureCodeUpgrades::get(&para_id), Some(expected_at));
				assert_eq!(<Paras as Store>::FutureCode::get(&para_id), Some(new_code.clone()));
				assert_eq!(Paras::current_code(&para_id), Some(vec![1, 2, 3].into()));

				expected_at
			};

			Paras::schedule_para_cleanup(para_id);

			// Just scheduling cleanup shouldn't change anything.
			{
				assert_eq!(<Paras as Store>::OutgoingParas::get(), vec![para_id]);
				assert_eq!(Paras::parachains(), vec![para_id]);

				assert!(Paras::past_code_meta(&para_id).most_recent_change().is_none());
				assert_eq!(<Paras as Store>::FutureCodeUpgrades::get(&para_id), Some(expected_at));
				assert_eq!(<Paras as Store>::FutureCode::get(&para_id), Some(new_code.clone()));
				assert_eq!(Paras::current_code(&para_id), Some(vec![1, 2, 3].into()));

				assert_eq!(<Paras as Store>::Heads::get(&para_id), Some(Default::default()));
			}

			// run to block, with a session change at that block.
			run_to_block(3, Some(vec![3]));

			// cleaning up the parachain should place the current parachain code
			// into the past code buffer & schedule cleanup.
			assert_eq!(Paras::past_code_meta(&para_id).most_recent_change(), Some(3));
			assert_eq!(<Paras as Store>::PastCode::get(&(para_id, 3)), Some(vec![1, 2, 3].into()));
			assert_eq!(<Paras as Store>::PastCodePruning::get(), vec![(para_id, 3)]);

			// any future upgrades haven't been used to validate yet, so those
			// are cleaned up immediately.
			assert!(<Paras as Store>::FutureCodeUpgrades::get(&para_id).is_none());
			assert!(<Paras as Store>::FutureCode::get(&para_id).is_none());
			assert!(Paras::current_code(&para_id).is_none());

			// run to do the final cleanup
			let cleaned_up_at = 3 + acceptance_period + 1;
			run_to_block(cleaned_up_at, None);

			// now the final cleanup: last past code cleaned up, and this triggers meta cleanup.
			assert_eq!(Paras::past_code_meta(&para_id), Default::default());
			assert!(<Paras as Store>::PastCode::get(&(para_id, 3)).is_none());
			assert!(<Paras as Store>::PastCodePruning::get().is_empty());
		});
	}

	#[test]
	fn para_incoming_at_session() {
		new_test_ext(Default::default()).execute_with(|| {
			run_to_block(1, None);

			let b = ParaId::from(525);
			let a = ParaId::from(999);
			let c = ParaId::from(333);

			Paras::schedule_para_initialize(
				b,
				ParaGenesisArgs {
					parachain: true,
					genesis_head: vec![1].into(),
					validation_code: vec![1].into(),
				},
			);

			Paras::schedule_para_initialize(
				a,
				ParaGenesisArgs {
					parachain: false,
					genesis_head: vec![2].into(),
					validation_code: vec![2].into(),
				},
			);

			Paras::schedule_para_initialize(
				c,
				ParaGenesisArgs {
					parachain: true,
					genesis_head: vec![3].into(),
					validation_code: vec![3].into(),
				},
			);

			assert_eq!(<Paras as Store>::UpcomingParas::get(), vec![c, b, a]);
			assert!(<Paras as Store>::Parathreads::get(&a).is_none());


			// run to block without session change.
			run_to_block(2, None);

			assert_eq!(Paras::parachains(), Vec::new());
			assert_eq!(<Paras as Store>::UpcomingParas::get(), vec![c, b, a]);
			assert!(<Paras as Store>::Parathreads::get(&a).is_none());


			run_to_block(3, Some(vec![3]));

			assert_eq!(Paras::parachains(), vec![c, b]);
			assert_eq!(<Paras as Store>::UpcomingParas::get(), Vec::new());

			assert!(<Paras as Store>::Parathreads::get(&a).is_some());

			assert_eq!(Paras::current_code(&a), Some(vec![2].into()));
			assert_eq!(Paras::current_code(&b), Some(vec![1].into()));
			assert_eq!(Paras::current_code(&c), Some(vec![3].into()));
		})
	}

	#[test]
	fn code_at_with_intermediate() {
		let acceptance_period = 10;

		let paras = vec![
			(0u32.into(), ParaGenesisArgs {
				parachain: true,
				genesis_head: Default::default(),
				validation_code: vec![1, 2, 3].into(),
			}),
		];

		let genesis_config = MockGenesisConfig {
			paras: GenesisConfig { paras, ..Default::default() },
			configuration: crate::configuration::GenesisConfig {
				config: HostConfiguration {
					acceptance_period,
					..Default::default()
				},
				..Default::default()
			},
			..Default::default()
		};

		new_test_ext(genesis_config).execute_with(|| {
			let para_id = ParaId::from(0);
			let old_code: ValidationCode = vec![1, 2, 3].into();
			let new_code: ValidationCode = vec![4, 5, 6].into();
			Paras::schedule_code_upgrade(para_id, new_code.clone(), 10);

			// no intermediate, falls back on current/past.
			assert_eq!(Paras::validation_code_at(para_id, 1, None), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 10, None), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 100, None), Some(old_code.clone()));

			// intermediate before upgrade meant to be applied, falls back on current.
			assert_eq!(Paras::validation_code_at(para_id, 9, Some(8)), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 10, Some(9)), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 11, Some(9)), Some(old_code.clone()));

			// intermediate at or after upgrade applied
			assert_eq!(Paras::validation_code_at(para_id, 11, Some(10)), Some(new_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 100, Some(11)), Some(new_code.clone()));

			run_to_block(acceptance_period + 5, None);

			// at <= intermediate not allowed
			assert_eq!(Paras::validation_code_at(para_id, 10, Some(10)), None);
			assert_eq!(Paras::validation_code_at(para_id, 9, Some(10)), None);
		});
	}

	#[test]
	fn code_at_returns_up_to_end_of_acceptance_period() {
		let acceptance_period = 10;

		let paras = vec![
			(0u32.into(), ParaGenesisArgs {
				parachain: true,
				genesis_head: Default::default(),
				validation_code: vec![1, 2, 3].into(),
			}),
		];

		let genesis_config = MockGenesisConfig {
			paras: GenesisConfig { paras, ..Default::default() },
			configuration: crate::configuration::GenesisConfig {
				config: HostConfiguration {
					acceptance_period,
					..Default::default()
				},
				..Default::default()
			},
			..Default::default()
		};

		new_test_ext(genesis_config).execute_with(|| {
			let para_id = ParaId::from(0);
			let old_code: ValidationCode = vec![1, 2, 3].into();
			let new_code: ValidationCode = vec![4, 5, 6].into();
			Paras::schedule_code_upgrade(para_id, new_code.clone(), 2);

			run_to_block(10, None);
			Paras::note_new_head(para_id, Default::default(), 7);

			assert_eq!(
				Paras::past_code_meta(&para_id).upgrade_times,
				vec![upgrade_at(2, 10)],
			);

			assert_eq!(Paras::validation_code_at(para_id, 2, None), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 3, None), Some(new_code.clone()));

			run_to_block(10 + acceptance_period, None);

			assert_eq!(Paras::validation_code_at(para_id, 2, None), Some(old_code.clone()));
			assert_eq!(Paras::validation_code_at(para_id, 3, None), Some(new_code.clone()));

			run_to_block(10 + acceptance_period + 1, None);

			// code entry should be pruned now.

			assert_eq!(
				Paras::past_code_meta(&para_id),
				ParaPastCodeMeta {
					upgrade_times: Vec::new(),
					last_pruned: Some(2),
				},
			);

			assert_eq!(Paras::validation_code_at(para_id, 2, None), None); // pruned :(
			assert_eq!(Paras::validation_code_at(para_id, 3, None), Some(new_code.clone()));
		});
	}
}