Merge pull request #228 from sigp/fork-choice

Fork choice longest chain update.

beacon_node/beacon_chain/test_harness/src/beacon_chain_harness.rs

@@ -6,7 +6,7 @@ use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     MemoryDB,
 };
-use fork_choice::{optimised_lmd_ghost::OptimisedLMDGhost, slow_lmd_ghost::SlowLMDGhost}; // import all the algorithms
+use fork_choice::OptimisedLMDGhost;
 use log::debug;
 use rayon::prelude::*;
 use slot_clock::TestingSlotClock;

beacon_node/beacon_chain/test_harness/src/validator_harness/mod.rs

@@ -10,7 +10,7 @@ use block_producer::{BlockProducer, Error as BlockPollError};
 use db::MemoryDB;
 use direct_beacon_node::DirectBeaconNode;
 use direct_duties::DirectDuties;
-use fork_choice::{optimised_lmd_ghost::OptimisedLMDGhost, slow_lmd_ghost::SlowLMDGhost};
+use fork_choice::OptimisedLMDGhost;
 use local_signer::LocalSigner;
 use slot_clock::TestingSlotClock;
 use std::sync::Arc;

eth2/fork_choice/Cargo.toml

@@ -10,3 +10,9 @@ ssz = { path = "../utils/ssz" }
 types = { path = "../types" }
 fast-math = "0.1.1"
 byteorder = "1.3.1"
+
+[dev-dependencies]
+yaml-rust = "0.4.2"
+bls = { path = "../utils/bls" }
+slot_clock = { path = "../utils/slot_clock" }
+beacon_chain = { path = "../../beacon_node/beacon_chain" }

eth2/fork_choice/src/lib.rs

@@ -44,13 +44,15 @@ extern crate types;
 
 pub mod longest_chain;
 pub mod optimised_lmd_ghost;
-pub mod protolambda_lmd_ghost;
 pub mod slow_lmd_ghost;
 
 use db::stores::BeaconBlockAtSlotError;
 use db::DBError;
 use types::{BeaconBlock, Hash256};
 
+pub use longest_chain::LongestChain;
+pub use optimised_lmd_ghost::OptimisedLMDGhost;
+
 /// Defines the interface for Fork Choices. Each Fork choice will define their own data structures
 /// which can be built in block processing through the `add_block` and `add_attestation` functions.
 /// The main fork choice algorithm is specified in `find_head
@@ -83,6 +85,7 @@ pub enum ForkChoiceError {
     CannotFindBestChild,
     ChildrenNotFound,
     StorageError(String),
+    HeadNotFound,
 }
 
 impl From<DBError> for ForkChoiceError {
@@ -113,6 +116,4 @@ pub enum ForkChoiceAlgorithms {
     SlowLMDGhost,
     /// An optimised version of LMD-GHOST by Vitalik.
     OptimisedLMDGhost,
-    /// An optimised version of LMD-GHOST by Protolambda.
-    ProtoLMDGhost,
 }

eth2/fork_choice/src/longest_chain.rs

@@ -1,52 +1,73 @@
-use db::stores::BeaconBlockStore;
+use crate::{ForkChoice, ForkChoiceError};
-use db::{ClientDB, DBError};
+use db::{stores::BeaconBlockStore, ClientDB};
-use ssz::{Decodable, DecodeError};
 use std::sync::Arc;
 use types::{BeaconBlock, Hash256, Slot};
 
-pub enum ForkChoiceError {
+pub struct LongestChain<T>
-    BadSszInDatabase,
-    MissingBlock,
-    DBError(String),
-}
-
-pub fn longest_chain<T>(
-    head_block_hashes: &[Hash256],
-    block_store: &Arc<BeaconBlockStore<T>>,
-) -> Result<Option<usize>, ForkChoiceError>
 where
     T: ClientDB + Sized,
 {
-    let mut head_blocks: Vec<(usize, BeaconBlock)> = vec![];
+    /// List of head block hashes
+    head_block_hashes: Vec<Hash256>,
+    /// Block storage access.
+    block_store: Arc<BeaconBlockStore<T>>,
+}
 
+impl<T> LongestChain<T>
+where
+    T: ClientDB + Sized,
+{
+    pub fn new(block_store: Arc<BeaconBlockStore<T>>) -> Self {
+        LongestChain {
+            head_block_hashes: Vec::new(),
+            block_store,
+        }
+    }
+}
+
+impl<T: ClientDB + Sized> ForkChoice for LongestChain<T> {
+    fn add_block(
+        &mut self,
+        block: &BeaconBlock,
+        block_hash: &Hash256,
+    ) -> Result<(), ForkChoiceError> {
+        // add the block hash to head_block_hashes removing the parent if it exists
+        self.head_block_hashes
+            .retain(|hash| *hash != block.parent_root);
+        self.head_block_hashes.push(*block_hash);
+        Ok(())
+    }
+
+    fn add_attestation(&mut self, _: u64, _: &Hash256) -> Result<(), ForkChoiceError> {
+        // do nothing
+        Ok(())
+    }
+
+    fn find_head(&mut self, _: &Hash256) -> Result<Hash256, ForkChoiceError> {
+        let mut head_blocks: Vec<(usize, BeaconBlock)> = vec![];
         /*
          * Load all the head_block hashes from the DB as SszBeaconBlocks.
          */
-    for (index, block_hash) in head_block_hashes.iter().enumerate() {
+        for (index, block_hash) in self.head_block_hashes.iter().enumerate() {
-        let ssz = block_store
+            let block = self
-            .get(&block_hash)?
+                .block_store
-            .ok_or(ForkChoiceError::MissingBlock)?;
+                .get_deserialized(&block_hash)?
-        let (block, _) = BeaconBlock::ssz_decode(&ssz, 0)?;
+                .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*block_hash))?;
             head_blocks.push((index, block));
         }
 
         /*
          * Loop through all the head blocks and find the highest slot.
          */
-    let highest_slot: Option<Slot> = None;
+        let highest_slot = head_blocks
-    for (_, block) in &head_blocks {
+            .iter()
-        let slot = block.slot;
+            .fold(Slot::from(0u64), |highest, (_, block)| {
+                std::cmp::max(block.slot, highest)
+            });
 
-        match highest_slot {
+        // if we find no blocks, return Error
-            None => Some(slot),
+        if highest_slot == 0 {
-            Some(winning_slot) => {
+            return Err(ForkChoiceError::HeadNotFound);
-                if slot > winning_slot {
-                    Some(slot)
-                } else {
-                    Some(winning_slot)
-                }
-            }
-        };
         }
 
         /*
@@ -55,39 +76,27 @@ where
          * Ultimately, the index of the head_block hash with the highest slot and highest block
          * hash will be the winner.
          */
-    match highest_slot {
+
-        None => Ok(None),
+        let head_index: Option<usize> =
-        Some(highest_slot) => {
+            head_blocks
-            let mut highest_blocks = vec![];
+                .iter()
-            for (index, block) in head_blocks {
+                .fold(None, |smallest_index, (index, block)| {
                     if block.slot == highest_slot {
-                    highest_blocks.push((index, block))
+                        if smallest_index.is_none() {
+                            return Some(*index);
                         }
+                        return Some(std::cmp::min(
+                            *index,
+                            smallest_index.expect("Cannot be None"),
+                        ));
+                    }
+                    smallest_index
+                });
+
+        if head_index.is_none() {
+            return Err(ForkChoiceError::HeadNotFound);
         }
 
-            highest_blocks.sort_by(|a, b| head_block_hashes[a.0].cmp(&head_block_hashes[b.0]));
+        Ok(self.head_block_hashes[head_index.unwrap()])
-            let (index, _) = highest_blocks[0];
-            Ok(Some(index))
-        }
-    }
-}
-
-impl From<DecodeError> for ForkChoiceError {
-    fn from(_: DecodeError) -> Self {
-        ForkChoiceError::BadSszInDatabase
-    }
-}
-
-impl From<DBError> for ForkChoiceError {
-    fn from(e: DBError) -> Self {
-        ForkChoiceError::DBError(e.message)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn test_naive_fork_choice() {
-        assert_eq!(2 + 2, 4);
     }
 }

eth2/fork_choice/src/optimised_lmd_ghost.rs

@@ -30,10 +30,8 @@ use fast_math::log2_raw;
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
-    readers::BeaconBlockReader,
+    readers::BeaconBlockReader, validator_registry::get_active_validator_indices, BeaconBlock,
-    slot_epoch_height::{Height, Slot},
+    Hash256, Slot, SlotHeight,
-    validator_registry::get_active_validator_indices,
-    BeaconBlock, Hash256,
 };
 
 //TODO: Pruning - Children
@@ -77,7 +75,7 @@ pub struct OptimisedLMDGhost<T: ClientDB + Sized> {
     block_store: Arc<BeaconBlockStore<T>>,
     /// State storage access.
     state_store: Arc<BeaconStateStore<T>>,
-    max_known_height: Height,
+    max_known_height: SlotHeight,
 }
 
 impl<T> OptimisedLMDGhost<T>
@@ -93,7 +91,7 @@ where
             ancestors: vec![HashMap::new(); 16],
             latest_attestation_targets: HashMap::new(),
             children: HashMap::new(),
-            max_known_height: Height::new(0),
+            max_known_height: SlotHeight::new(0),
             block_store,
             state_store,
         }
@@ -118,7 +116,7 @@ where
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
         let active_validator_indices = get_active_validator_indices(
-            &current_state.validator_registry,
+            &current_state.validator_registry[..],
             block_slot.epoch(EPOCH_LENGTH),
         );
 
@@ -137,7 +135,7 @@ where
     }
 
     /// Gets the ancestor at a given height `at_height` of a block specified by `block_hash`.
-    fn get_ancestor(&mut self, block_hash: Hash256, at_height: Height) -> Option<Hash256> {
+    fn get_ancestor(&mut self, block_hash: Hash256, at_height: SlotHeight) -> Option<Hash256> {
         // return None if we can't get the block from the db.
         let block_height = {
             let block_slot = self
@@ -186,7 +184,7 @@ where
     fn get_clear_winner(
         &mut self,
         latest_votes: &HashMap<Hash256, u64>,
-        block_height: Height,
+        block_height: SlotHeight,
     ) -> Option<Hash256> {
         // map of vote counts for every hash at this height
         let mut current_votes: HashMap<Hash256, u64> = HashMap::new();

eth2/fork_choice/src/slow_lmd_ghost.rs

@@ -28,10 +28,8 @@ use db::{
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
-    readers::{BeaconBlockReader, BeaconStateReader},
+    readers::BeaconBlockReader, validator_registry::get_active_validator_indices, BeaconBlock,
-    slot_epoch_height::Slot,
+    Hash256, Slot,
-    validator_registry::get_active_validator_indices,
-    BeaconBlock, Hash256,
 };
 
 //TODO: Pruning and syncing

eth2/types/src/lib.rs

@@ -24,6 +24,8 @@ pub mod readers;
 pub mod shard_reassignment_record;
 pub mod slashable_attestation;
 pub mod slashable_vote_data;
+#[macro_use]
+pub mod slot_epoch_macros;
 pub mod slot_epoch;
 pub mod slot_height;
 pub mod spec;

eth2/types/src/slot_epoch.rs

@@ -21,255 +21,6 @@ use std::hash::{Hash, Hasher};
 use std::iter::Iterator;
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, Sub, SubAssign};
 
-macro_rules! impl_from_into_u64 {
-    ($main: ident) => {
-        impl From<u64> for $main {
-            fn from(n: u64) -> $main {
-                $main(n)
-            }
-        }
-
-        impl Into<u64> for $main {
-            fn into(self) -> u64 {
-                self.0
-            }
-        }
-
-        impl $main {
-            pub fn as_u64(&self) -> u64 {
-                self.0
-            }
-        }
-    };
-}
-
-macro_rules! impl_from_into_usize {
-    ($main: ident) => {
-        impl From<usize> for $main {
-            fn from(n: usize) -> $main {
-                $main(n as u64)
-            }
-        }
-
-        impl Into<usize> for $main {
-            fn into(self) -> usize {
-                self.0 as usize
-            }
-        }
-
-        impl $main {
-            pub fn as_usize(&self) -> usize {
-                self.0 as usize
-            }
-        }
-    };
-}
-
-macro_rules! impl_math_between {
-    ($main: ident, $other: ident) => {
-        impl PartialOrd<$other> for $main {
-            /// Utilizes `partial_cmp` on the underlying `u64`.
-            fn partial_cmp(&self, other: &$other) -> Option<Ordering> {
-                Some(self.0.cmp(&(*other).into()))
-            }
-        }
-
-        impl PartialEq<$other> for $main {
-            fn eq(&self, other: &$other) -> bool {
-                let other: u64 = (*other).into();
-                self.0 == other
-            }
-        }
-
-        impl Add<$other> for $main {
-            type Output = $main;
-
-            fn add(self, other: $other) -> $main {
-                $main::from(self.0.saturating_add(other.into()))
-            }
-        }
-
-        impl AddAssign<$other> for $main {
-            fn add_assign(&mut self, other: $other) {
-                self.0 = self.0.saturating_add(other.into());
-            }
-        }
-
-        impl Sub<$other> for $main {
-            type Output = $main;
-
-            fn sub(self, other: $other) -> $main {
-                $main::from(self.0.saturating_sub(other.into()))
-            }
-        }
-
-        impl SubAssign<$other> for $main {
-            fn sub_assign(&mut self, other: $other) {
-                self.0 = self.0.saturating_sub(other.into());
-            }
-        }
-
-        impl Mul<$other> for $main {
-            type Output = $main;
-
-            fn mul(self, rhs: $other) -> $main {
-                let rhs: u64 = rhs.into();
-                $main::from(self.0.saturating_mul(rhs))
-            }
-        }
-
-        impl MulAssign<$other> for $main {
-            fn mul_assign(&mut self, rhs: $other) {
-                let rhs: u64 = rhs.into();
-                self.0 = self.0.saturating_mul(rhs)
-            }
-        }
-
-        impl Div<$other> for $main {
-            type Output = $main;
-
-            fn div(self, rhs: $other) -> $main {
-                let rhs: u64 = rhs.into();
-                if rhs == 0 {
-                    panic!("Cannot divide by zero-valued Slot/Epoch")
-                }
-                $main::from(self.0 / rhs)
-            }
-        }
-
-        impl DivAssign<$other> for $main {
-            fn div_assign(&mut self, rhs: $other) {
-                let rhs: u64 = rhs.into();
-                if rhs == 0 {
-                    panic!("Cannot divide by zero-valued Slot/Epoch")
-                }
-                self.0 = self.0 / rhs
-            }
-        }
-
-        impl Rem<$other> for $main {
-            type Output = $main;
-
-            fn rem(self, modulus: $other) -> $main {
-                let modulus: u64 = modulus.into();
-                $main::from(self.0 % modulus)
-            }
-        }
-    };
-}
-
-macro_rules! impl_math {
-    ($type: ident) => {
-        impl $type {
-            pub fn saturating_sub<T: Into<$type>>(&self, other: T) -> $type {
-                *self - other.into()
-            }
-
-            pub fn saturating_add<T: Into<$type>>(&self, other: T) -> $type {
-                *self + other.into()
-            }
-
-            pub fn checked_div<T: Into<$type>>(&self, rhs: T) -> Option<$type> {
-                let rhs: $type = rhs.into();
-                if rhs == 0 {
-                    None
-                } else {
-                    Some(*self / rhs)
-                }
-            }
-
-            pub fn is_power_of_two(&self) -> bool {
-                self.0.is_power_of_two()
-            }
-        }
-
-        impl Ord for $type {
-            fn cmp(&self, other: &$type) -> Ordering {
-                let other: u64 = (*other).into();
-                self.0.cmp(&other)
-            }
-        }
-    };
-}
-
-macro_rules! impl_display {
-    ($type: ident) => {
-        impl fmt::Display for $type {
-            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-                write!(f, "{}", self.0)
-            }
-        }
-
-        impl slog::Value for $type {
-            fn serialize(
-                &self,
-                record: &slog::Record,
-                key: slog::Key,
-                serializer: &mut slog::Serializer,
-            ) -> slog::Result {
-                self.0.serialize(record, key, serializer)
-            }
-        }
-    };
-}
-
-macro_rules! impl_ssz {
-    ($type: ident) => {
-        impl Encodable for $type {
-            fn ssz_append(&self, s: &mut SszStream) {
-                s.append(&self.0);
-            }
-        }
-
-        impl Decodable for $type {
-            fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-                let (value, i) = <_>::ssz_decode(bytes, i)?;
-
-                Ok(($type(value), i))
-            }
-        }
-
-        impl TreeHash for $type {
-            fn hash_tree_root(&self) -> Vec<u8> {
-                let mut result: Vec<u8> = vec![];
-                result.append(&mut self.0.hash_tree_root());
-                hash(&result)
-            }
-        }
-
-        impl<T: RngCore> TestRandom<T> for $type {
-            fn random_for_test(rng: &mut T) -> Self {
-                $type::from(u64::random_for_test(rng))
-            }
-        }
-    };
-}
-
-macro_rules! impl_hash {
-    ($type: ident) => {
-        // Implemented to stop clippy lint:
-        // https://rust-lang.github.io/rust-clippy/master/index.html#derive_hash_xor_eq
-        impl Hash for $type {
-            fn hash<H: Hasher>(&self, state: &mut H) {
-                ssz_encode(self).hash(state)
-            }
-        }
-    };
-}
-
-macro_rules! impl_common {
-    ($type: ident) => {
-        impl_from_into_u64!($type);
-        impl_from_into_usize!($type);
-        impl_math_between!($type, $type);
-        impl_math_between!($type, u64);
-        impl_math!($type);
-        impl_display!($type);
-        impl_ssz!($type);
-        impl_hash!($type);
-    };
-}
-
 #[derive(Eq, Debug, Clone, Copy, Default, Serialize)]
 pub struct Slot(u64);
 
@@ -349,373 +100,19 @@ impl<'a> Iterator for SlotIter<'a> {
 }
 
 #[cfg(test)]
-mod tests {
+mod slot_tests {
-    use super::*;
-
-    macro_rules! new_tests {
-        ($type: ident) => {
-            #[test]
-            fn new() {
-                assert_eq!($type(0), $type::new(0));
-                assert_eq!($type(3), $type::new(3));
-                assert_eq!($type(u64::max_value()), $type::new(u64::max_value()));
-            }
-        };
-    }
-
-    macro_rules! from_into_tests {
-        ($type: ident, $other: ident) => {
-            #[test]
-            fn into() {
-                let x: $other = $type(0).into();
-                assert_eq!(x, 0);
-
-                let x: $other = $type(3).into();
-                assert_eq!(x, 3);
-
-                let x: $other = $type(u64::max_value()).into();
-                // Note: this will fail on 32 bit systems. This is expected as we don't have a proper
-                // 32-bit system strategy in place.
-                assert_eq!(x, $other::max_value());
-            }
-
-            #[test]
-            fn from() {
-                assert_eq!($type(0), $type::from(0_u64));
-                assert_eq!($type(3), $type::from(3_u64));
-                assert_eq!($type(u64::max_value()), $type::from($other::max_value()));
-            }
-        };
-    }
-
-    macro_rules! math_between_tests {
-        ($type: ident, $other: ident) => {
-            #[test]
-            fn partial_ord() {
-                let assert_partial_ord = |a: u64, partial_ord: Ordering, b: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a).partial_cmp(&other), Some(partial_ord));
-                };
-
-                assert_partial_ord(1, Ordering::Less, 2);
-                assert_partial_ord(2, Ordering::Greater, 1);
-                assert_partial_ord(0, Ordering::Less, u64::max_value());
-                assert_partial_ord(u64::max_value(), Ordering::Greater, 0);
-            }
-
-            #[test]
-            fn partial_eq() {
-                let assert_partial_eq = |a: u64, b: u64, is_equal: bool| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a).eq(&other), is_equal);
-                };
-
-                assert_partial_eq(0, 0, true);
-                assert_partial_eq(0, 1, false);
-                assert_partial_eq(1, 0, false);
-                assert_partial_eq(1, 1, true);
-
-                assert_partial_eq(u64::max_value(), u64::max_value(), true);
-                assert_partial_eq(0, u64::max_value(), false);
-                assert_partial_eq(u64::max_value(), 0, false);
-            }
-
-            #[test]
-            fn add_and_add_assign() {
-                let assert_add = |a: u64, b: u64, result: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a) + other, $type(result));
-
-                    let mut add_assigned = $type(a);
-                    add_assigned += other;
-
-                    assert_eq!(add_assigned, $type(result));
-                };
-
-                assert_add(0, 1, 1);
-                assert_add(1, 0, 1);
-                assert_add(1, 2, 3);
-                assert_add(2, 1, 3);
-                assert_add(7, 7, 14);
-
-                // Addition should be saturating.
-                assert_add(u64::max_value(), 1, u64::max_value());
-                assert_add(u64::max_value(), u64::max_value(), u64::max_value());
-            }
-
-            #[test]
-            fn sub_and_sub_assign() {
-                let assert_sub = |a: u64, b: u64, result: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a) - other, $type(result));
-
-                    let mut sub_assigned = $type(a);
-                    sub_assigned -= other;
-
-                    assert_eq!(sub_assigned, $type(result));
-                };
-
-                assert_sub(1, 0, 1);
-                assert_sub(2, 1, 1);
-                assert_sub(14, 7, 7);
-                assert_sub(u64::max_value(), 1, u64::max_value() - 1);
-                assert_sub(u64::max_value(), u64::max_value(), 0);
-
-                // Subtraction should be saturating
-                assert_sub(0, 1, 0);
-                assert_sub(1, 2, 0);
-            }
-
-            #[test]
-            fn mul_and_mul_assign() {
-                let assert_mul = |a: u64, b: u64, result: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a) * other, $type(result));
-
-                    let mut mul_assigned = $type(a);
-                    mul_assigned *= other;
-
-                    assert_eq!(mul_assigned, $type(result));
-                };
-
-                assert_mul(2, 2, 4);
-                assert_mul(1, 2, 2);
-                assert_mul(0, 2, 0);
-
-                // Multiplication should be saturating.
-                assert_mul(u64::max_value(), 2, u64::max_value());
-            }
-
-            #[test]
-            fn div_and_div_assign() {
-                let assert_div = |a: u64, b: u64, result: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a) / other, $type(result));
-
-                    let mut div_assigned = $type(a);
-                    div_assigned /= other;
-
-                    assert_eq!(div_assigned, $type(result));
-                };
-
-                assert_div(0, 2, 0);
-                assert_div(2, 2, 1);
-                assert_div(100, 50, 2);
-                assert_div(128, 2, 64);
-                assert_div(u64::max_value(), 2, 2_u64.pow(63) - 1);
-            }
-
-            #[test]
-            #[should_panic]
-            fn div_panics_with_divide_by_zero() {
-                let other: $other = $type(0).into();
-                let _ = $type(2) / other;
-            }
-
-            #[test]
-            #[should_panic]
-            fn div_assign_panics_with_divide_by_zero() {
-                let other: $other = $type(0).into();
-                let mut assigned = $type(2);
-                assigned /= other;
-            }
-
-            #[test]
-            fn rem() {
-                let assert_rem = |a: u64, b: u64, result: u64| {
-                    let other: $other = $type(b).into();
-                    assert_eq!($type(a) % other, $type(result));
-                };
-
-                assert_rem(3, 2, 1);
-                assert_rem(40, 2, 0);
-                assert_rem(10, 100, 10);
-                assert_rem(302042, 3293, 2379);
-            }
-        };
-    }
-
-    macro_rules! math_tests {
-        ($type: ident) => {
-            #[test]
-            fn saturating_sub() {
-                let assert_saturating_sub = |a: u64, b: u64, result: u64| {
-                    assert_eq!($type(a).saturating_sub($type(b)), $type(result));
-                };
-
-                assert_saturating_sub(1, 0, 1);
-                assert_saturating_sub(2, 1, 1);
-                assert_saturating_sub(14, 7, 7);
-                assert_saturating_sub(u64::max_value(), 1, u64::max_value() - 1);
-                assert_saturating_sub(u64::max_value(), u64::max_value(), 0);
-
-                // Subtraction should be saturating
-                assert_saturating_sub(0, 1, 0);
-                assert_saturating_sub(1, 2, 0);
-            }
-
-            #[test]
-            fn saturating_add() {
-                let assert_saturating_add = |a: u64, b: u64, result: u64| {
-                    assert_eq!($type(a).saturating_add($type(b)), $type(result));
-                };
-
-                assert_saturating_add(0, 1, 1);
-                assert_saturating_add(1, 0, 1);
-                assert_saturating_add(1, 2, 3);
-                assert_saturating_add(2, 1, 3);
-                assert_saturating_add(7, 7, 14);
-
-                // Addition should be saturating.
-                assert_saturating_add(u64::max_value(), 1, u64::max_value());
-                assert_saturating_add(u64::max_value(), u64::max_value(), u64::max_value());
-            }
-
-            #[test]
-            fn checked_div() {
-                let assert_checked_div = |a: u64, b: u64, result: Option<u64>| {
-                    let division_result_as_u64 = match $type(a).checked_div($type(b)) {
-                        None => None,
-                        Some(val) => Some(val.as_u64()),
-                    };
-                    assert_eq!(division_result_as_u64, result);
-                };
-
-                assert_checked_div(0, 2, Some(0));
-                assert_checked_div(2, 2, Some(1));
-                assert_checked_div(100, 50, Some(2));
-                assert_checked_div(128, 2, Some(64));
-                assert_checked_div(u64::max_value(), 2, Some(2_u64.pow(63) - 1));
-
-                assert_checked_div(2, 0, None);
-                assert_checked_div(0, 0, None);
-                assert_checked_div(u64::max_value(), 0, None);
-            }
-
-            #[test]
-            fn is_power_of_two() {
-                let assert_is_power_of_two = |a: u64, result: bool| {
-                    assert_eq!(
-                        $type(a).is_power_of_two(),
-                        result,
-                        "{}.is_power_of_two() != {}",
-                        a,
-                        result
-                    );
-                };
-
-                assert_is_power_of_two(0, false);
-                assert_is_power_of_two(1, true);
-                assert_is_power_of_two(2, true);
-                assert_is_power_of_two(3, false);
-                assert_is_power_of_two(4, true);
-
-                assert_is_power_of_two(2_u64.pow(4), true);
-                assert_is_power_of_two(u64::max_value(), false);
-            }
-
-            #[test]
-            fn ord() {
-                let assert_ord = |a: u64, ord: Ordering, b: u64| {
-                    assert_eq!($type(a).cmp(&$type(b)), ord);
-                };
-
-                assert_ord(1, Ordering::Less, 2);
-                assert_ord(2, Ordering::Greater, 1);
-                assert_ord(0, Ordering::Less, u64::max_value());
-                assert_ord(u64::max_value(), Ordering::Greater, 0);
-            }
-        };
-    }
-
-    macro_rules! ssz_tests {
-        ($type: ident) => {
-            #[test]
-            pub fn test_ssz_round_trip() {
-                let mut rng = XorShiftRng::from_seed([42; 16]);
-                let original = $type::random_for_test(&mut rng);
-
-                let bytes = ssz_encode(&original);
-                let (decoded, _) = $type::ssz_decode(&bytes, 0).unwrap();
-
-                assert_eq!(original, decoded);
-            }
-
-            #[test]
-            pub fn test_hash_tree_root() {
-                let mut rng = XorShiftRng::from_seed([42; 16]);
-                let original = $type::random_for_test(&mut rng);
-
-                let result = original.hash_tree_root();
-
-                assert_eq!(result.len(), 32);
-                // TODO: Add further tests
-                // https://github.com/sigp/lighthouse/issues/170
-            }
-        };
-    }
-
-    macro_rules! all_tests {
-        ($type: ident) => {
-            new_tests!($type);
-            math_between_tests!($type, $type);
-            math_tests!($type);
-            ssz_tests!($type);
-
-            mod u64_tests {
-                use super::*;
-
-                from_into_tests!($type, u64);
-                math_between_tests!($type, u64);
-
-                #[test]
-                pub fn as_64() {
-                    let x = $type(0).as_u64();
-                    assert_eq!(x, 0);
-
-                    let x = $type(3).as_u64();
-                    assert_eq!(x, 3);
-
-                    let x = $type(u64::max_value()).as_u64();
-                    assert_eq!(x, u64::max_value());
-                }
-            }
-
-            mod usize_tests {
-                use super::*;
-
-                from_into_tests!($type, usize);
-
-                #[test]
-                pub fn as_usize() {
-                    let x = $type(0).as_usize();
-                    assert_eq!(x, 0);
-
-                    let x = $type(3).as_usize();
-                    assert_eq!(x, 3);
-
-                    let x = $type(u64::max_value()).as_usize();
-                    assert_eq!(x, usize::max_value());
-                }
-            }
-        };
-    }
-
-    #[cfg(test)]
-    mod slot_tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
     use ssz::ssz_encode;
 
     all_tests!(Slot);
-    }
+}
 
-    #[cfg(test)]
+#[cfg(test)]
-    mod epoch_tests {
+mod epoch_tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
     use ssz::ssz_encode;
 
     all_tests!(Epoch);
-    }
 }

eth2/types/src/slot_epoch_macros.rs

@@ -0,0 +1,621 @@
+macro_rules! impl_from_into_u64 {
+    ($main: ident) => {
+        impl From<u64> for $main {
+            fn from(n: u64) -> $main {
+                $main(n)
+            }
+        }
+
+        impl Into<u64> for $main {
+            fn into(self) -> u64 {
+                self.0
+            }
+        }
+
+        impl $main {
+            pub fn as_u64(&self) -> u64 {
+                self.0
+            }
+        }
+    };
+}
+
+// need to truncate for some fork-choice algorithms
+macro_rules! impl_into_u32 {
+    ($main: ident) => {
+        impl Into<u32> for $main {
+            fn into(self) -> u32 {
+                self.0 as u32
+            }
+        }
+
+        impl $main {
+            pub fn as_u32(&self) -> u32 {
+                self.0 as u32
+            }
+        }
+    };
+}
+
+macro_rules! impl_from_into_usize {
+    ($main: ident) => {
+        impl From<usize> for $main {
+            fn from(n: usize) -> $main {
+                $main(n as u64)
+            }
+        }
+
+        impl Into<usize> for $main {
+            fn into(self) -> usize {
+                self.0 as usize
+            }
+        }
+
+        impl $main {
+            pub fn as_usize(&self) -> usize {
+                self.0 as usize
+            }
+        }
+    };
+}
+
+macro_rules! impl_math_between {
+    ($main: ident, $other: ident) => {
+        impl PartialOrd<$other> for $main {
+            /// Utilizes `partial_cmp` on the underlying `u64`.
+            fn partial_cmp(&self, other: &$other) -> Option<Ordering> {
+                Some(self.0.cmp(&(*other).into()))
+            }
+        }
+
+        impl PartialEq<$other> for $main {
+            fn eq(&self, other: &$other) -> bool {
+                let other: u64 = (*other).into();
+                self.0 == other
+            }
+        }
+
+        impl Add<$other> for $main {
+            type Output = $main;
+
+            fn add(self, other: $other) -> $main {
+                $main::from(self.0.saturating_add(other.into()))
+            }
+        }
+
+        impl AddAssign<$other> for $main {
+            fn add_assign(&mut self, other: $other) {
+                self.0 = self.0.saturating_add(other.into());
+            }
+        }
+
+        impl Sub<$other> for $main {
+            type Output = $main;
+
+            fn sub(self, other: $other) -> $main {
+                $main::from(self.0.saturating_sub(other.into()))
+            }
+        }
+
+        impl SubAssign<$other> for $main {
+            fn sub_assign(&mut self, other: $other) {
+                self.0 = self.0.saturating_sub(other.into());
+            }
+        }
+
+        impl Mul<$other> for $main {
+            type Output = $main;
+
+            fn mul(self, rhs: $other) -> $main {
+                let rhs: u64 = rhs.into();
+                $main::from(self.0.saturating_mul(rhs))
+            }
+        }
+
+        impl MulAssign<$other> for $main {
+            fn mul_assign(&mut self, rhs: $other) {
+                let rhs: u64 = rhs.into();
+                self.0 = self.0.saturating_mul(rhs)
+            }
+        }
+
+        impl Div<$other> for $main {
+            type Output = $main;
+
+            fn div(self, rhs: $other) -> $main {
+                let rhs: u64 = rhs.into();
+                if rhs == 0 {
+                    panic!("Cannot divide by zero-valued Slot/Epoch")
+                }
+                $main::from(self.0 / rhs)
+            }
+        }
+
+        impl DivAssign<$other> for $main {
+            fn div_assign(&mut self, rhs: $other) {
+                let rhs: u64 = rhs.into();
+                if rhs == 0 {
+                    panic!("Cannot divide by zero-valued Slot/Epoch")
+                }
+                self.0 = self.0 / rhs
+            }
+        }
+
+        impl Rem<$other> for $main {
+            type Output = $main;
+
+            fn rem(self, modulus: $other) -> $main {
+                let modulus: u64 = modulus.into();
+                $main::from(self.0 % modulus)
+            }
+        }
+    };
+}
+
+macro_rules! impl_math {
+    ($type: ident) => {
+        impl $type {
+            pub fn saturating_sub<T: Into<$type>>(&self, other: T) -> $type {
+                *self - other.into()
+            }
+
+            pub fn saturating_add<T: Into<$type>>(&self, other: T) -> $type {
+                *self + other.into()
+            }
+
+            pub fn checked_div<T: Into<$type>>(&self, rhs: T) -> Option<$type> {
+                let rhs: $type = rhs.into();
+                if rhs == 0 {
+                    None
+                } else {
+                    Some(*self / rhs)
+                }
+            }
+
+            pub fn is_power_of_two(&self) -> bool {
+                self.0.is_power_of_two()
+            }
+        }
+
+        impl Ord for $type {
+            fn cmp(&self, other: &$type) -> Ordering {
+                let other: u64 = (*other).into();
+                self.0.cmp(&other)
+            }
+        }
+    };
+}
+
+macro_rules! impl_display {
+    ($type: ident) => {
+        impl fmt::Display for $type {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                write!(f, "{}", self.0)
+            }
+        }
+
+        impl slog::Value for $type {
+            fn serialize(
+                &self,
+                record: &slog::Record,
+                key: slog::Key,
+                serializer: &mut slog::Serializer,
+            ) -> slog::Result {
+                self.0.serialize(record, key, serializer)
+            }
+        }
+    };
+}
+
+macro_rules! impl_ssz {
+    ($type: ident) => {
+        impl Encodable for $type {
+            fn ssz_append(&self, s: &mut SszStream) {
+                s.append(&self.0);
+            }
+        }
+
+        impl Decodable for $type {
+            fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
+                let (value, i) = <_>::ssz_decode(bytes, i)?;
+
+                Ok(($type(value), i))
+            }
+        }
+
+        impl TreeHash for $type {
+            fn hash_tree_root(&self) -> Vec<u8> {
+                let mut result: Vec<u8> = vec![];
+                result.append(&mut self.0.hash_tree_root());
+                hash(&result)
+            }
+        }
+
+        impl<T: RngCore> TestRandom<T> for $type {
+            fn random_for_test(rng: &mut T) -> Self {
+                $type::from(u64::random_for_test(rng))
+            }
+        }
+    };
+}
+
+macro_rules! impl_hash {
+    ($type: ident) => {
+        // Implemented to stop clippy lint:
+        // https://rust-lang.github.io/rust-clippy/master/index.html#derive_hash_xor_eq
+        impl Hash for $type {
+            fn hash<H: Hasher>(&self, state: &mut H) {
+                ssz_encode(self).hash(state)
+            }
+        }
+    };
+}
+
+macro_rules! impl_common {
+    ($type: ident) => {
+        impl_from_into_u64!($type);
+        impl_from_into_usize!($type);
+        impl_math_between!($type, $type);
+        impl_math_between!($type, u64);
+        impl_math!($type);
+        impl_display!($type);
+        impl_ssz!($type);
+        impl_hash!($type);
+    };
+}
+
+// test macros
+#[allow(unused_macros)]
+macro_rules! new_tests {
+    ($type: ident) => {
+        #[test]
+        fn new() {
+            assert_eq!($type(0), $type::new(0));
+            assert_eq!($type(3), $type::new(3));
+            assert_eq!($type(u64::max_value()), $type::new(u64::max_value()));
+        }
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! from_into_tests {
+    ($type: ident, $other: ident) => {
+        #[test]
+        fn into() {
+            let x: $other = $type(0).into();
+            assert_eq!(x, 0);
+
+            let x: $other = $type(3).into();
+            assert_eq!(x, 3);
+
+            let x: $other = $type(u64::max_value()).into();
+            // Note: this will fail on 32 bit systems. This is expected as we don't have a proper
+            // 32-bit system strategy in place.
+            assert_eq!(x, $other::max_value());
+        }
+
+        #[test]
+        fn from() {
+            assert_eq!($type(0), $type::from(0_u64));
+            assert_eq!($type(3), $type::from(3_u64));
+            assert_eq!($type(u64::max_value()), $type::from($other::max_value()));
+        }
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! math_between_tests {
+    ($type: ident, $other: ident) => {
+        #[test]
+        fn partial_ord() {
+            let assert_partial_ord = |a: u64, partial_ord: Ordering, b: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a).partial_cmp(&other), Some(partial_ord));
+            };
+
+            assert_partial_ord(1, Ordering::Less, 2);
+            assert_partial_ord(2, Ordering::Greater, 1);
+            assert_partial_ord(0, Ordering::Less, u64::max_value());
+            assert_partial_ord(u64::max_value(), Ordering::Greater, 0);
+        }
+
+        #[test]
+        fn partial_eq() {
+            let assert_partial_eq = |a: u64, b: u64, is_equal: bool| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a).eq(&other), is_equal);
+            };
+
+            assert_partial_eq(0, 0, true);
+            assert_partial_eq(0, 1, false);
+            assert_partial_eq(1, 0, false);
+            assert_partial_eq(1, 1, true);
+
+            assert_partial_eq(u64::max_value(), u64::max_value(), true);
+            assert_partial_eq(0, u64::max_value(), false);
+            assert_partial_eq(u64::max_value(), 0, false);
+        }
+
+        #[test]
+        fn add_and_add_assign() {
+            let assert_add = |a: u64, b: u64, result: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a) + other, $type(result));
+
+                let mut add_assigned = $type(a);
+                add_assigned += other;
+
+                assert_eq!(add_assigned, $type(result));
+            };
+
+            assert_add(0, 1, 1);
+            assert_add(1, 0, 1);
+            assert_add(1, 2, 3);
+            assert_add(2, 1, 3);
+            assert_add(7, 7, 14);
+
+            // Addition should be saturating.
+            assert_add(u64::max_value(), 1, u64::max_value());
+            assert_add(u64::max_value(), u64::max_value(), u64::max_value());
+        }
+
+        #[test]
+        fn sub_and_sub_assign() {
+            let assert_sub = |a: u64, b: u64, result: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a) - other, $type(result));
+
+                let mut sub_assigned = $type(a);
+                sub_assigned -= other;
+
+                assert_eq!(sub_assigned, $type(result));
+            };
+
+            assert_sub(1, 0, 1);
+            assert_sub(2, 1, 1);
+            assert_sub(14, 7, 7);
+            assert_sub(u64::max_value(), 1, u64::max_value() - 1);
+            assert_sub(u64::max_value(), u64::max_value(), 0);
+
+            // Subtraction should be saturating
+            assert_sub(0, 1, 0);
+            assert_sub(1, 2, 0);
+        }
+
+        #[test]
+        fn mul_and_mul_assign() {
+            let assert_mul = |a: u64, b: u64, result: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a) * other, $type(result));
+
+                let mut mul_assigned = $type(a);
+                mul_assigned *= other;
+
+                assert_eq!(mul_assigned, $type(result));
+            };
+
+            assert_mul(2, 2, 4);
+            assert_mul(1, 2, 2);
+            assert_mul(0, 2, 0);
+
+            // Multiplication should be saturating.
+            assert_mul(u64::max_value(), 2, u64::max_value());
+        }
+
+        #[test]
+        fn div_and_div_assign() {
+            let assert_div = |a: u64, b: u64, result: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a) / other, $type(result));
+
+                let mut div_assigned = $type(a);
+                div_assigned /= other;
+
+                assert_eq!(div_assigned, $type(result));
+            };
+
+            assert_div(0, 2, 0);
+            assert_div(2, 2, 1);
+            assert_div(100, 50, 2);
+            assert_div(128, 2, 64);
+            assert_div(u64::max_value(), 2, 2_u64.pow(63) - 1);
+        }
+
+        #[test]
+        #[should_panic]
+        fn div_panics_with_divide_by_zero() {
+            let other: $other = $type(0).into();
+            let _ = $type(2) / other;
+        }
+
+        #[test]
+        #[should_panic]
+        fn div_assign_panics_with_divide_by_zero() {
+            let other: $other = $type(0).into();
+            let mut assigned = $type(2);
+            assigned /= other;
+        }
+
+        #[test]
+        fn rem() {
+            let assert_rem = |a: u64, b: u64, result: u64| {
+                let other: $other = $type(b).into();
+                assert_eq!($type(a) % other, $type(result));
+            };
+
+            assert_rem(3, 2, 1);
+            assert_rem(40, 2, 0);
+            assert_rem(10, 100, 10);
+            assert_rem(302042, 3293, 2379);
+        }
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! math_tests {
+    ($type: ident) => {
+        #[test]
+        fn saturating_sub() {
+            let assert_saturating_sub = |a: u64, b: u64, result: u64| {
+                assert_eq!($type(a).saturating_sub($type(b)), $type(result));
+            };
+
+            assert_saturating_sub(1, 0, 1);
+            assert_saturating_sub(2, 1, 1);
+            assert_saturating_sub(14, 7, 7);
+            assert_saturating_sub(u64::max_value(), 1, u64::max_value() - 1);
+            assert_saturating_sub(u64::max_value(), u64::max_value(), 0);
+
+            // Subtraction should be saturating
+            assert_saturating_sub(0, 1, 0);
+            assert_saturating_sub(1, 2, 0);
+        }
+
+        #[test]
+        fn saturating_add() {
+            let assert_saturating_add = |a: u64, b: u64, result: u64| {
+                assert_eq!($type(a).saturating_add($type(b)), $type(result));
+            };
+
+            assert_saturating_add(0, 1, 1);
+            assert_saturating_add(1, 0, 1);
+            assert_saturating_add(1, 2, 3);
+            assert_saturating_add(2, 1, 3);
+            assert_saturating_add(7, 7, 14);
+
+            // Addition should be saturating.
+            assert_saturating_add(u64::max_value(), 1, u64::max_value());
+            assert_saturating_add(u64::max_value(), u64::max_value(), u64::max_value());
+        }
+
+        #[test]
+        fn checked_div() {
+            let assert_checked_div = |a: u64, b: u64, result: Option<u64>| {
+                let division_result_as_u64 = match $type(a).checked_div($type(b)) {
+                    None => None,
+                    Some(val) => Some(val.as_u64()),
+                };
+                assert_eq!(division_result_as_u64, result);
+            };
+
+            assert_checked_div(0, 2, Some(0));
+            assert_checked_div(2, 2, Some(1));
+            assert_checked_div(100, 50, Some(2));
+            assert_checked_div(128, 2, Some(64));
+            assert_checked_div(u64::max_value(), 2, Some(2_u64.pow(63) - 1));
+
+            assert_checked_div(2, 0, None);
+            assert_checked_div(0, 0, None);
+            assert_checked_div(u64::max_value(), 0, None);
+        }
+
+        #[test]
+        fn is_power_of_two() {
+            let assert_is_power_of_two = |a: u64, result: bool| {
+                assert_eq!(
+                    $type(a).is_power_of_two(),
+                    result,
+                    "{}.is_power_of_two() != {}",
+                    a,
+                    result
+                );
+            };
+
+            assert_is_power_of_two(0, false);
+            assert_is_power_of_two(1, true);
+            assert_is_power_of_two(2, true);
+            assert_is_power_of_two(3, false);
+            assert_is_power_of_two(4, true);
+
+            assert_is_power_of_two(2_u64.pow(4), true);
+            assert_is_power_of_two(u64::max_value(), false);
+        }
+
+        #[test]
+        fn ord() {
+            let assert_ord = |a: u64, ord: Ordering, b: u64| {
+                assert_eq!($type(a).cmp(&$type(b)), ord);
+            };
+
+            assert_ord(1, Ordering::Less, 2);
+            assert_ord(2, Ordering::Greater, 1);
+            assert_ord(0, Ordering::Less, u64::max_value());
+            assert_ord(u64::max_value(), Ordering::Greater, 0);
+        }
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! ssz_tests {
+    ($type: ident) => {
+        #[test]
+        pub fn test_ssz_round_trip() {
+            let mut rng = XorShiftRng::from_seed([42; 16]);
+            let original = $type::random_for_test(&mut rng);
+
+            let bytes = ssz_encode(&original);
+            let (decoded, _) = $type::ssz_decode(&bytes, 0).unwrap();
+
+            assert_eq!(original, decoded);
+        }
+
+        #[test]
+        pub fn test_hash_tree_root() {
+            let mut rng = XorShiftRng::from_seed([42; 16]);
+            let original = $type::random_for_test(&mut rng);
+
+            let result = original.hash_tree_root();
+
+            assert_eq!(result.len(), 32);
+            // TODO: Add further tests
+            // https://github.com/sigp/lighthouse/issues/170
+        }
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! all_tests {
+    ($type: ident) => {
+        new_tests!($type);
+        math_between_tests!($type, $type);
+        math_tests!($type);
+        ssz_tests!($type);
+
+        mod u64_tests {
+            use super::*;
+
+            from_into_tests!($type, u64);
+            math_between_tests!($type, u64);
+
+            #[test]
+            pub fn as_64() {
+                let x = $type(0).as_u64();
+                assert_eq!(x, 0);
+
+                let x = $type(3).as_u64();
+                assert_eq!(x, 3);
+
+                let x = $type(u64::max_value()).as_u64();
+                assert_eq!(x, u64::max_value());
+            }
+        }
+
+        mod usize_tests {
+            use super::*;
+
+            from_into_tests!($type, usize);
+
+            #[test]
+            pub fn as_usize() {
+                let x = $type(0).as_usize();
+                assert_eq!(x, 0);
+
+                let x = $type(3).as_usize();
+                assert_eq!(x, 3);
+
+                let x = $type(u64::max_value()).as_usize();
+                assert_eq!(x, usize::max_value());
+            }
+        }
+    };
+}

eth2/types/src/slot_height.rs

@@ -1,290 +1,13 @@
-// Copyright 2019 Sigma Prime Pty Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the "Software"),
-// to deal in the Software without restriction, including without limitation
-// the rights to use, copy, modify, merge, publish, distribute, sublicense,
-// and/or sell copies of the Software, and to permit persons to whom the
-// Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
 use crate::slot_epoch::{Epoch, Slot};
+use crate::test_utils::TestRandom;
+use rand::RngCore;
 use serde_derive::Serialize;
-use slog;
 use ssz::{hash, ssz_encode, Decodable, DecodeError, Encodable, SszStream, TreeHash};
 use std::cmp::{Ord, Ordering};
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, Sub, SubAssign};
 
-macro_rules! impl_from_into_u64 {
-    ($main: ident) => {
-        impl From<u64> for $main {
-            fn from(n: u64) -> $main {
-                $main(n)
-            }
-        }
-
-        impl Into<u64> for $main {
-            fn into(self) -> u64 {
-                self.0
-            }
-        }
-
-        impl $main {
-            pub fn as_u64(&self) -> u64 {
-                self.0
-            }
-        }
-    };
-}
-
-// need to truncate for some fork-choice algorithms
-macro_rules! impl_into_u32 {
-    ($main: ident) => {
-        impl Into<u32> for $main {
-            fn into(self) -> u32 {
-                self.0 as u32
-            }
-        }
-
-        impl $main {
-            pub fn as_u32(&self) -> u32 {
-                self.0 as u32
-            }
-        }
-    };
-}
-macro_rules! impl_from_into_usize {
-    ($main: ident) => {
-        impl From<usize> for $main {
-            fn from(n: usize) -> $main {
-                $main(n as u64)
-            }
-        }
-
-        impl Into<usize> for $main {
-            fn into(self) -> usize {
-                self.0 as usize
-            }
-        }
-
-        impl $main {
-            pub fn as_usize(&self) -> usize {
-                self.0 as usize
-            }
-        }
-    };
-}
-
-macro_rules! impl_math_between {
-    ($main: ident, $other: ident) => {
-        impl PartialOrd<$other> for $main {
-            /// Utilizes `partial_cmp` on the underlying `u64`.
-            fn partial_cmp(&self, other: &$other) -> Option<Ordering> {
-                Some(self.0.cmp(&(*other).into()))
-            }
-        }
-
-        impl PartialEq<$other> for $main {
-            fn eq(&self, other: &$other) -> bool {
-                let other: u64 = (*other).into();
-                self.0 == other
-            }
-        }
-
-        impl Add<$other> for $main {
-            type Output = $main;
-
-            fn add(self, other: $other) -> $main {
-                $main::from(self.0.saturating_add(other.into()))
-            }
-        }
-
-        impl AddAssign<$other> for $main {
-            fn add_assign(&mut self, other: $other) {
-                self.0 = self.0.saturating_add(other.into());
-            }
-        }
-
-        impl Sub<$other> for $main {
-            type Output = $main;
-
-            fn sub(self, other: $other) -> $main {
-                $main::from(self.0.saturating_sub(other.into()))
-            }
-        }
-
-        impl SubAssign<$other> for $main {
-            fn sub_assign(&mut self, other: $other) {
-                self.0 = self.0.saturating_sub(other.into());
-            }
-        }
-
-        impl Mul<$other> for $main {
-            type Output = $main;
-
-            fn mul(self, rhs: $other) -> $main {
-                let rhs: u64 = rhs.into();
-                $main::from(self.0.saturating_mul(rhs))
-            }
-        }
-
-        impl MulAssign<$other> for $main {
-            fn mul_assign(&mut self, rhs: $other) {
-                let rhs: u64 = rhs.into();
-                self.0 = self.0.saturating_mul(rhs)
-            }
-        }
-
-        impl Div<$other> for $main {
-            type Output = $main;
-
-            fn div(self, rhs: $other) -> $main {
-                let rhs: u64 = rhs.into();
-                if rhs == 0 {
-                    panic!("Cannot divide by zero-valued Slot/Epoch")
-                }
-                $main::from(self.0 / rhs)
-            }
-        }
-
-        impl DivAssign<$other> for $main {
-            fn div_assign(&mut self, rhs: $other) {
-                let rhs: u64 = rhs.into();
-                if rhs == 0 {
-                    panic!("Cannot divide by zero-valued Slot/Epoch")
-                }
-                self.0 = self.0 / rhs
-            }
-        }
-
-        impl Rem<$other> for $main {
-            type Output = $main;
-
-            fn rem(self, modulus: $other) -> $main {
-                let modulus: u64 = modulus.into();
-                $main::from(self.0 % modulus)
-            }
-        }
-    };
-}
-
-macro_rules! impl_math {
-    ($type: ident) => {
-        impl $type {
-            pub fn saturating_sub<T: Into<$type>>(&self, other: T) -> $type {
-                *self - other.into()
-            }
-
-            pub fn saturating_add<T: Into<$type>>(&self, other: T) -> $type {
-                *self + other.into()
-            }
-
-            pub fn checked_div<T: Into<$type>>(&self, rhs: T) -> Option<$type> {
-                let rhs: $type = rhs.into();
-                if rhs == 0 {
-                    None
-                } else {
-                    Some(*self / rhs)
-                }
-            }
-
-            pub fn is_power_of_two(&self) -> bool {
-                self.0.is_power_of_two()
-            }
-        }
-
-        impl Ord for $type {
-            fn cmp(&self, other: &$type) -> Ordering {
-                let other: u64 = (*other).into();
-                self.0.cmp(&other)
-            }
-        }
-    };
-}
-
-macro_rules! impl_display {
-    ($type: ident) => {
-        impl fmt::Display for $type {
-            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-                write!(f, "{}", self.0)
-            }
-        }
-
-        impl slog::Value for $type {
-            fn serialize(
-                &self,
-                record: &slog::Record,
-                key: slog::Key,
-                serializer: &mut slog::Serializer,
-            ) -> slog::Result {
-                self.0.serialize(record, key, serializer)
-            }
-        }
-    };
-}
-
-macro_rules! impl_ssz {
-    ($type: ident) => {
-        impl Encodable for $type {
-            fn ssz_append(&self, s: &mut SszStream) {
-                s.append(&self.0);
-            }
-        }
-
-        impl Decodable for $type {
-            fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-                let (value, i) = <_>::ssz_decode(bytes, i)?;
-
-                Ok(($type(value), i))
-            }
-        }
-
-        impl TreeHash for $type {
-            fn hash_tree_root(&self) -> Vec<u8> {
-                let mut result: Vec<u8> = vec![];
-                result.append(&mut self.0.hash_tree_root());
-                hash(&result)
-            }
-        }
-    };
-}
-
-macro_rules! impl_hash {
-    ($type: ident) => {
-        // Implemented to stop clippy lint:
-        // https://rust-lang.github.io/rust-clippy/master/index.html#derive_hash_xor_eq
-        impl Hash for $type {
-            fn hash<H: Hasher>(&self, state: &mut H) {
-                ssz_encode(self).hash(state)
-            }
-        }
-    };
-}
-
-macro_rules! impl_common {
-    ($type: ident) => {
-        impl_from_into_u64!($type);
-        impl_from_into_usize!($type);
-        impl_math_between!($type, $type);
-        impl_math_between!($type, u64);
-        impl_math!($type);
-        impl_display!($type);
-        impl_ssz!($type);
-        impl_hash!($type);
-    };
-}
 /// Beacon block height, effectively `Slot/GENESIS_START_BLOCK`.
 #[derive(Eq, Debug, Clone, Copy, Default, Serialize)]
 pub struct SlotHeight(u64);
@@ -309,3 +32,13 @@ impl SlotHeight {
         SlotHeight(u64::max_value())
     }
 }
+
+#[cfg(test)]
+
+mod slot_height_tests {
+    use super::*;
+    use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
+    use ssz::ssz_encode;
+
+    all_tests!(SlotHeight);
+}