diff --git a/tests/core/pyspec/eth2spec/test/phase1/block_processing/test_process_shard_transition.py b/tests/core/pyspec/eth2spec/test/phase1/block_processing/test_process_shard_transition.py
index 0f610c161..b14b836c0 100644
--- a/tests/core/pyspec/eth2spec/test/phase1/block_processing/test_process_shard_transition.py
+++ b/tests/core/pyspec/eth2spec/test/phase1/block_processing/test_process_shard_transition.py
@@ -7,7 +7,6 @@ from eth2spec.test.helpers.attestations import (
     get_valid_attestation,
     get_valid_on_time_attestation,
     run_attestation_processing,
-    sign_aggregate_attestation,
 )
 from eth2spec.test.helpers.shard_transitions import run_shard_transitions_processing
 from eth2spec.test.helpers.shard_block import (
@@ -140,17 +139,12 @@ def test_no_winning_root(spec, state):
         spec, state,
         index=committee_index,
         shard_transition=shard_transition,
+        # Decrease attested participants to 1/3 committee
+        filter_participant_set=lambda committee: set(list(committee)[:len(committee) // 3]),
         signed=True,
         on_time=True,
     )
 
-    # Decrease attested participants to 1/3 committee
-    beacon_committee = spec.get_beacon_committee(state, state.slot, committee_index)
-    attested_participants = beacon_committee[:len(beacon_committee) // 3]
-    for i in range(len(beacon_committee)):
-        attestation.aggregation_bits[i] = beacon_committee[i] in attested_participants
-    attestation.signature = sign_aggregate_attestation(spec, state, attestation.data, attested_participants)
-
     next_slot(spec, state)
 
     _, _, _ = run_attestation_processing(spec, state, attestation)