Fix parallelism bug in exit processing (#1110)

* Fix parallelism bug in exit processing

Also:

* Remove parallelism for all other operations except deposit merkle proofs
* Improve exit tests
* Fix broken attestation test

Closes #1090

* Allow for generating block/pre/post states from some unit tests (#1123)

* Add post-state checks, comments

* Add state_transition_vectors crate

* Integrate new testing crate with CI

* Add readme

* Add additional valid tests

* Remove ExitTests (they were moved to new crate)

* Small test fixes

* Delete incorrect saturating_sub in slash_validator

And clean-up the balance increase/decrease functions to look more like the spec.

Co-authored-by: Paul Hauner <paul@paulhauner.com>

eth2/types/src/slot_epoch.rs

@@ -35,7 +35,7 @@ impl_common!(Slot);
 impl_common!(Epoch);
 
 impl Slot {
-    pub fn new(slot: u64) -> Slot {
+    pub const fn new(slot: u64) -> Slot {
         Slot(slot)
     }
 
@@ -49,7 +49,7 @@ impl Slot {
 }
 
 impl Epoch {
-    pub fn new(slot: u64) -> Epoch {
+    pub const fn new(slot: u64) -> Epoch {
         Epoch(slot)
     }
 

eth2/types/src/test_utils/builders/testing_attestation_data_builder.rs

@@ -48,9 +48,6 @@ impl TestingAttestationDataBuilder {
         let beacon_block_root = *state.get_block_root(slot).unwrap();
 
         match test_task {
-            // FIXME: re-enable the shard-like tests
-            // AttestationTestTask::NoCommiteeForShard => index += 2,
-            // AttestationTestTask::BadShard => index = T::ShardCount::to_u64(),
             AttestationTestTask::IncludedTooEarly => {
                 slot = state.slot - spec.min_attestation_inclusion_delay + 1
             }

eth2/types/src/test_utils/builders/testing_beacon_block_builder.rs

@@ -28,25 +28,11 @@ pub enum DepositTestTask {
     NoReset,
 }
 
-/// Enum used for passing test options to builder
-#[derive(PartialEq, Clone, Copy)]
-pub enum ExitTestTask {
-    AlreadyInitiated,
-    AlreadyExited,
-    BadSignature,
-    FutureEpoch,
-    NotActive,
-    Valid,
-    ValidatorUnknown,
-}
-
 /// Enum used for passing test options to builder
 #[derive(PartialEq, Clone, Copy)]
 pub enum AttestationTestTask {
     Valid,
-    NoCommiteeForShard,
     WrongJustifiedCheckpoint,
-    BadShard,
     BadIndexedAttestationBadSignature,
     BadAggregationBitfieldLen,
     BadSignature,
@@ -348,39 +334,25 @@ impl<T: EthSpec> TestingBeaconBlockBuilder<T> {
         }
     }
 
-    /// Insert a `Valid` exit into the state.
+    /// Insert an exit for the given validator at the given epoch into the block.
     pub fn insert_exit(
         &mut self,
-        test_task: ExitTestTask,
-        state: &mut BeaconState<T>,
-        mut validator_index: u64,
+        validator_index: u64,
+        exit_epoch: Epoch,
         secret_key: &SecretKey,
+        state: &BeaconState<T>,
         spec: &ChainSpec,
     ) {
-        let sk = &mut secret_key.clone();
-        let mut exit_epoch = state.slot.epoch(T::slots_per_epoch());
-
-        match test_task {
-            ExitTestTask::BadSignature => *sk = SecretKey::random(),
-            ExitTestTask::ValidatorUnknown => validator_index = 4242,
-            ExitTestTask::AlreadyExited => {
-                state.validators[validator_index as usize].exit_epoch = Epoch::from(314_159 as u64)
-            }
-            // FIXME: disabled in v0.9
-            ExitTestTask::NotActive => {
-                state.validators[validator_index as usize].activation_epoch =
-                    Epoch::from(314_159 as u64)
-            }
-            ExitTestTask::FutureEpoch => exit_epoch = spec.far_future_epoch,
-            _ => (),
-        }
-
         let builder = TestingVoluntaryExitBuilder::new(exit_epoch, validator_index);
-        let exit = builder.build(sk, &state.fork, state.genesis_validators_root, spec);
-
+        let exit = builder.build(secret_key, &state.fork, state.genesis_validators_root, spec);
         self.block.body.voluntary_exits.push(exit).unwrap();
     }
 
+    /// Mutate the block before signing.
+    pub fn modify(&mut self, f: impl FnOnce(&mut BeaconBlock<T>)) {
+        f(&mut self.block)
+    }
+
     /// Signs and returns the block, consuming the builder.
     pub fn build(
         self,

eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs

@@ -164,9 +164,10 @@ impl<T: EthSpec> TestingBeaconStateBuilder<T> {
     }
 
     /// Sets the `BeaconState` to be in a slot, calling `teleport_to_epoch` to update the epoch.
-    pub fn teleport_to_slot(&mut self, slot: Slot) {
+    pub fn teleport_to_slot(&mut self, slot: Slot) -> &mut Self {
         self.teleport_to_epoch(slot.epoch(T::slots_per_epoch()));
         self.state.slot = slot;
+        self
     }
 
     /// Sets the `BeaconState` to be in the first slot of the given epoch.