diff --git a/eth2/types/src/beacon_state.rs b/eth2/types/src/beacon_state.rs
index aac95d37d2..f709bc68fa 100644
--- a/eth2/types/src/beacon_state.rs
+++ b/eth2/types/src/beacon_state.rs
@@ -51,9 +51,9 @@ pub enum Error {
         registry_len: usize,
     },
     PreviousEpochCacheUninitialized,
-    CurrentEpochCacheUnintialized,
+    CurrentEpochCacheUninitialized,
     RelativeEpochError(RelativeEpochError),
-    EpochCacheUnintialized(RelativeEpoch),
+    EpochCacheUninitialized(RelativeEpoch),
     EpochCacheError(EpochCacheError),
     TreeHashCacheError(TreeHashCacheError),
 }
@@ -706,8 +706,9 @@ impl<T: EthSpec> BeaconState<T> {
     pub fn get_attestation_duties(
         &self,
         validator_index: usize,
+        relative_epoch: RelativeEpoch,
     ) -> Result<&Option<AttestationDuty>, Error> {
-        let cache = self.cache(RelativeEpoch::Current)?;
+        let cache = self.cache(relative_epoch)?;
 
         Ok(cache
             .attestation_duties
@@ -799,10 +800,15 @@ impl<T: EthSpec> BeaconState<T> {
         if cache.is_initialized_at(relative_epoch.into_epoch(self.current_epoch())) {
             Ok(cache)
         } else {
-            Err(Error::EpochCacheUnintialized(relative_epoch))
+            Err(Error::EpochCacheUninitialized(relative_epoch))
         }
     }
 
+    /// Drops the cache, leaving it in an uninitialized state.
+    fn drop_cache(&mut self, relative_epoch: RelativeEpoch) {
+        self.epoch_caches[Self::cache_index(relative_epoch)] = EpochCache::default();
+    }
+
     // FIXME(sproul): drop_previous/current_epoch_cache
 
     /// Updates the pubkey cache, if required.
diff --git a/eth2/types/src/beacon_state/epoch_cache/tests.rs b/eth2/types/src/beacon_state/epoch_cache/tests.rs
index c1187e8ff9..df8ed223b5 100644
--- a/eth2/types/src/beacon_state/epoch_cache/tests.rs
+++ b/eth2/types/src/beacon_state/epoch_cache/tests.rs
@@ -111,6 +111,8 @@ fn can_start_on_any_shard() {
     }
 }
 
+/// This spec has more shards than slots in an epoch, permitting epochs where not all shards are
+/// included in the committee.
 #[derive(Clone, PartialEq, Debug, Default, Serialize, Deserialize)]
 pub struct ExcessShardsEthSpec;
 
diff --git a/eth2/types/src/beacon_state/tests.rs b/eth2/types/src/beacon_state/tests.rs
index 753f8bf8e1..35f0269b1f 100644
--- a/eth2/types/src/beacon_state/tests.rs
+++ b/eth2/types/src/beacon_state/tests.rs
@@ -72,7 +72,6 @@ fn get_active_index_root_index() {
     test_active_index::<FoundationEthSpec>(slot);
 }
 
-/*
 /// Test that
 ///
 /// 1. Using the cache before it's built fails.
@@ -89,14 +88,12 @@ fn test_cache_initialization<'a, T: EthSpec>(
 
     // Assuming the cache isn't already built, assert that a call to a cache-using function fails.
     assert_eq!(
-        state.get_attestation_duties(0, spec),
+        state.get_attestation_duties(0, relative_epoch),
         Err(BeaconStateError::EpochCacheUninitialized(relative_epoch))
     );
 
     // Build the cache.
-    state
-        .build_current_epoch_cache(relative_epoch, spec)
-        .unwrap();
+    state.build_epoch_cache(relative_epoch, spec).unwrap();
 
     // Assert a call to a cache-using function passes.
     let _ = state
@@ -125,10 +122,8 @@ fn cache_initialization() {
 
     test_cache_initialization(&mut state, RelativeEpoch::Previous, &spec);
     test_cache_initialization(&mut state, RelativeEpoch::Current, &spec);
-    test_cache_initialization(&mut state, RelativeEpoch::NextWithRegistryChange, &spec);
-    test_cache_initialization(&mut state, RelativeEpoch::NextWithoutRegistryChange, &spec);
+    test_cache_initialization(&mut state, RelativeEpoch::Next, &spec);
 }
-*/
 
 #[test]
 fn tree_hash_cache() {
@@ -208,13 +203,23 @@ mod committees {
                 );
 
                 // Loop through each validator in the committee.
-                for &i in cc.committee {
+                for (committee_i, validator_i) in cc.committee.iter().enumerate() {
                     // Assert the validators are assigned contiguously across committees.
                     assert_eq!(
-                        i,
+                        *validator_i,
                         *expected_indices_iter.next().unwrap(),
                         "Non-sequential validators."
                     );
+                    // Assert a call to `get_attestation_duties` is consistent with a call to
+                    // `get_crosslink_committees_at_slot`
+                    let attestation_duty = state
+                        .get_attestation_duties(*validator_i, relative_epoch)
+                        .unwrap()
+                        .unwrap();
+                    assert_eq!(attestation_duty.slot, slot);
+                    assert_eq!(attestation_duty.shard, cc.shard);
+                    assert_eq!(attestation_duty.committee_index, committee_i);
+                    assert_eq!(attestation_duty.committee_len, cc.committee.len());
                 }
             }
         }