diff --git a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
index 95f00edd4..f0fe35e8b 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_justification_and_finalization.py
@@ -1,3 +1,4 @@
+import math
 from eth2spec.test.context import spec_state_test, with_all_phases
 from eth2spec.test.phase_0.epoch_processing.run_epoch_process_base import (
     run_epoch_processing_with
@@ -8,41 +9,46 @@ def run_process_just_and_fin(spec, state):
     yield from run_epoch_processing_with(spec, state, 'process_justification_and_finalization')
 
 
-def get_committee_size(spec, state, slot):
+def get_shards_for_slot(spec, state, slot):
     epoch = spec.slot_to_epoch(slot)
     epoch_start_shard = spec.get_epoch_start_shard(state, epoch)
     committees_per_slot = spec.get_epoch_committee_count(state, epoch) // spec.SLOTS_PER_EPOCH
     shard = (epoch_start_shard + committees_per_slot * (slot % spec.SLOTS_PER_EPOCH)) % spec.SHARD_COUNT
-    committee_index = (shard + spec.SHARD_COUNT - spec.get_epoch_start_shard(state, epoch)) % spec.SHARD_COUNT
-    committee_count = spec.get_epoch_committee_count(state, epoch)
-    indices = spec.get_active_validator_indices(state, epoch)
+    return [shard + i for i in range(committees_per_slot)]
+
+
+def get_committee_size(spec, epoch_start_shard, shard, committee_count, indices):
+    committee_index = (shard + spec.SHARD_COUNT - epoch_start_shard) % spec.SHARD_COUNT
     start = (len(indices) * committee_index) // committee_count
     end = (len(indices) * (committee_index + 1)) // committee_count
     size = end - start
-    return size
+    return size,
 
 
-def add_mock_attestations(spec, state, target_epoch, att_count, att_ratio):
+def add_mock_attestations(spec, state, epoch, att_count, att_ratio):
     # we must be at the end of the epoch
     assert (state.slot + 1) % spec.SLOTS_PER_EPOCH == 0
 
     previous_epoch = spec.get_previous_epoch(state)
     current_epoch = spec.get_current_epoch(state)
 
-    if current_epoch == target_epoch:
+    if current_epoch == epoch:
         attestations = state.current_epoch_attestations
-    elif previous_epoch == target_epoch:
+    elif previous_epoch == epoch:
         attestations = state.previous_epoch_attestations
     else:
-        raise Exception(f"cannot target epoch ${target_epoch} from epoch ${current_epoch}")
+        raise Exception(f"cannot include attestations in epoch ${epoch} from epoch ${current_epoch}")
 
+    committee_count = spec.get_epoch_committee_count(state, epoch)
+    indices = spec.get_active_validator_indices(state, epoch)
+    epoch_start_shard = spec.get_epoch_start_shard(state, epoch)
     total = 0
-    while total < att_count:
-        for i in range(spec.SLOTS_PER_EPOCH):
-            size = get_committee_size(spec, state, state.slot + i)
+    for i in range(spec.SLOTS_PER_EPOCH):
+        for shard in get_shards_for_slot(spec, state, state.slot + i):
+            size = get_committee_size(spec, epoch_start_shard, shard, committee_count, indices)
             # Create a bitfield filled with the given count per attestation,
             #  exactly on the right-most part of the committee field.
-            attesting_count = int(size * att_ratio)
+            attesting_count = math.ceil(size * att_ratio)
             aggregation_bitfield = ((1 << attesting_count) - 1).to_bytes(length=((size + 7) // 8), byteorder='big')
 
             attestations.append(spec.PendingAttestation(
@@ -54,16 +60,20 @@ def add_mock_attestations(spec, state, target_epoch, att_count, att_ratio):
                     target_root=b'\xbb' * 32,
                     crosslink=spec.Crosslink()
                 ),
-                inclusion_delay=0,
+                inclusion_delay=1,
             ))
             total += 1
+            if total >= att_count:
+                return
+
+    raise Exception(f"could not fill state with {att_count} attestations for epoch {epoch}")
 
 
 @with_all_phases
 @spec_state_test
 def test_rule_1(spec, state):
-    previous_epoch = spec.get_previous_epoch(state)
-    current_epoch = spec.get_current_epoch(state)
+    # previous_epoch = spec.get_previous_epoch(state)
+    # current_epoch = spec.get_current_epoch(state)
 
     # TODO
     # add_mock_attestations(spec, state, ...)
@@ -71,4 +81,4 @@ def test_rule_1(spec, state):
     # set their balances
     # yield from run_process_just_and_fin(spec, state)
     # check finalization
-
+    pass