BABE refactoring: split out verification (#3658)

* Refactor parts of BABE verification into separate module

* Fix silly compiler error

* Move more of the verification code to verification.rs

* Remove some unused imports

* Fix line width

* fix testsuite compile error

* Fix compile errors in tests

* Move authorship-related code to its own files

* fix compile errors in tests

* Respond to review comments by @rphmeier

* improve docs

* fix compile error

* Add missing doc comment

substrate/core/consensus/babe/src/tests.rs

@@ -20,6 +20,7 @@
 // https://github.com/paritytech/substrate/issues/2532
 #![allow(deprecated)]
 use super::*;
+use authorship::claim_slot;
 
 use babe_primitives::{AuthorityPair, SlotNumber};
 use client::block_builder::BlockBuilder;
@@ -80,7 +81,7 @@ impl Environment<TestBlock> for DummyFactory {
 		-> Result<DummyProposer, Error>
 	{
 
-		let parent_slot = crate::find_pre_digest::<TestBlock>(parent_header)
+		let parent_slot = crate::find_pre_digest(parent_header)
 			.expect("parent header has a pre-digest")
 			.slot_number();
 
@@ -97,6 +98,7 @@ impl DummyProposer {
 	fn propose_with(&mut self, pre_digests: DigestFor<TestBlock>)
 		-> future::Ready<Result<TestBlock, Error>>
 	{
+		use codec::Encode;
 		let block_builder = self.factory.client.new_block_at(
 			&BlockId::Hash(self.parent_hash),
 			pre_digests,
@@ -106,7 +108,7 @@ impl DummyProposer {
 			Err(e) => return future::ready(Err(e)),
 		};
 
-		let this_slot = crate::find_pre_digest::<TestBlock>(block.header())
+		let this_slot = crate::find_pre_digest(block.header())
 			.expect("baked block has valid pre-digest")
 			.slot_number();