diff --git a/tests/core/pyspec/eth2spec/test/altair/light_client/test_sync.py b/tests/core/pyspec/eth2spec/test/altair/light_client/test_sync.py
index 47348717b..f8acdb13c 100644
--- a/tests/core/pyspec/eth2spec/test/altair/light_client/test_sync.py
+++ b/tests/core/pyspec/eth2spec/test/altair/light_client/test_sync.py
@@ -110,7 +110,7 @@ def compute_start_slot_at_sync_committee_period(spec, sync_committee_period):
 
 
 def compute_start_slot_at_next_sync_committee_period(spec, state):
-    sync_committee_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(state.slot))
+    sync_committee_period = spec.compute_sync_committee_period_at_slot(state.slot)
     return compute_start_slot_at_sync_committee_period(spec, sync_committee_period + 1)
 
 
diff --git a/tests/core/pyspec/eth2spec/test/altair/unittests/light_client/test_sync_protocol.py b/tests/core/pyspec/eth2spec/test/altair/unittests/light_client/test_sync_protocol.py
index e7845292a..e4df8a6d0 100644
--- a/tests/core/pyspec/eth2spec/test/altair/unittests/light_client/test_sync_protocol.py
+++ b/tests/core/pyspec/eth2spec/test/altair/unittests/light_client/test_sync_protocol.py
@@ -68,8 +68,8 @@ def test_process_light_client_update_at_period_boundary(spec, state):
 
     # Forward to slot before next sync committee period so that next block is final one in period
     next_slots(spec, state, spec.UPDATE_TIMEOUT - 2)
-    store_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(store.optimistic_header.slot))
-    update_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(state.slot))
+    store_period = spec.compute_sync_committee_period_at_slot(store.optimistic_header.slot)
+    update_period = spec.compute_sync_committee_period_at_slot(state.slot)
     assert store_period == update_period
 
     attested_block = state_transition_with_full_block(spec, state, False, False)
@@ -112,8 +112,8 @@ def test_process_light_client_update_timeout(spec, state):
 
     # Forward to next sync committee period
     next_slots(spec, state, spec.UPDATE_TIMEOUT)
-    store_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(store.optimistic_header.slot))
-    update_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(state.slot))
+    store_period = spec.compute_sync_committee_period_at_slot(store.optimistic_header.slot)
+    update_period = spec.compute_sync_committee_period_at_slot(state.slot)
     assert store_period + 1 == update_period
 
     attested_block = state_transition_with_full_block(spec, state, False, False)
@@ -164,8 +164,8 @@ def test_process_light_client_update_finality_updated(spec, state):
     # Ensure that finality checkpoint has changed
     assert state.finalized_checkpoint.epoch == 3
     # Ensure that it's same period
-    store_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(store.optimistic_header.slot))
-    update_period = spec.compute_sync_committee_period(spec.compute_epoch_at_slot(state.slot))
+    store_period = spec.compute_sync_committee_period_at_slot(store.optimistic_header.slot)
+    update_period = spec.compute_sync_committee_period_at_slot(state.slot)
     assert store_period == update_period
 
     attested_block = blocks[-1]