diff --git a/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
index 407455a0a..0c85bd1e2 100644
--- a/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
@@ -98,4 +98,4 @@ def test_inactivity_scores(spec, state):
     yield 'post', state
 
     for pre, post in zip(previous_inactivity_scores, state.inactivity_scores):
-        assert post == pre + spec.INACTIVITY_SCORE_BIAS
+        assert post == pre + spec.config.INACTIVITY_SCORE_BIAS
diff --git a/tests/core/pyspec/eth2spec/test/altair/transition/test_transition.py b/tests/core/pyspec/eth2spec/test/altair/transition/test_transition.py
index c3b03d663..aa2f0694b 100644
--- a/tests/core/pyspec/eth2spec/test/altair/transition/test_transition.py
+++ b/tests/core/pyspec/eth2spec/test/altair/transition/test_transition.py
@@ -69,8 +69,8 @@ def _do_altair_fork(state, spec, post_spec, fork_epoch, with_block=True):
     state = post_spec.upgrade_to_altair(state)
 
     assert state.fork.epoch == fork_epoch
-    assert state.fork.previous_version == post_spec.GENESIS_FORK_VERSION
-    assert state.fork.current_version == post_spec.ALTAIR_FORK_VERSION
+    assert state.fork.previous_version == post_spec.config.GENESIS_FORK_VERSION
+    assert state.fork.current_version == post_spec.config.ALTAIR_FORK_VERSION
 
     if with_block:
         return state, _state_transition_and_sign_block_at_slot(post_spec, state)
diff --git a/tests/core/pyspec/eth2spec/test/helpers/altair/fork.py b/tests/core/pyspec/eth2spec/test/helpers/altair/fork.py
index b1074c881..78f37c50e 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/altair/fork.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/altair/fork.py
@@ -36,7 +36,7 @@ def run_fork_test(post_spec, pre_state):
         assert getattr(pre_state, field) != getattr(post_state, field)
 
     assert pre_state.fork.current_version == post_state.fork.previous_version
-    assert post_state.fork.current_version == post_spec.ALTAIR_FORK_VERSION
+    assert post_state.fork.current_version == post_spec.config.ALTAIR_FORK_VERSION
     assert post_state.fork.epoch == post_spec.get_current_epoch(post_state)
 
     yield 'post', post_state
diff --git a/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py b/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
index f3b80b2ac..f6b007894 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
@@ -10,7 +10,7 @@ def get_anchor_root(spec, state):
 
 def add_block_to_store(spec, store, signed_block):
     pre_state = store.block_states[signed_block.message.parent_root]
-    block_time = pre_state.genesis_time + signed_block.message.slot * spec.SECONDS_PER_SLOT
+    block_time = pre_state.genesis_time + signed_block.message.slot * spec.config.SECONDS_PER_SLOT
 
     if store.time < block_time:
         spec.on_tick(store, block_time)
@@ -23,7 +23,7 @@ def tick_and_run_on_block(spec, store, signed_block, test_steps=None):
         test_steps = []
 
     pre_state = store.block_states[signed_block.message.parent_root]
-    block_time = pre_state.genesis_time + signed_block.message.slot * spec.SECONDS_PER_SLOT
+    block_time = pre_state.genesis_time + signed_block.message.slot * spec.config.SECONDS_PER_SLOT
 
     if store.time < block_time:
         on_tick_and_append_step(spec, store, block_time, test_steps)
@@ -37,8 +37,8 @@ def tick_and_run_on_attestation(spec, store, attestation, test_steps=None):
 
     parent_block = store.blocks[attestation.data.beacon_block_root]
     pre_state = store.block_states[spec.hash_tree_root(parent_block)]
-    block_time = pre_state.genesis_time + parent_block.slot * spec.SECONDS_PER_SLOT
-    next_epoch_time = block_time + spec.SLOTS_PER_EPOCH * spec.SECONDS_PER_SLOT
+    block_time = pre_state.genesis_time + parent_block.slot * spec.config.SECONDS_PER_SLOT
+    next_epoch_time = block_time + spec.SLOTS_PER_EPOCH * spec.config.SECONDS_PER_SLOT
 
     if store.time < next_epoch_time:
         spec.on_tick(store, next_epoch_time)
diff --git a/tests/core/pyspec/eth2spec/test/helpers/genesis.py b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
index c57442766..8617ce9f3 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/genesis.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
@@ -25,12 +25,12 @@ def create_genesis_state(spec, validator_balances, activation_threshold):
     deposit_root = b'\x42' * 32
 
     eth1_block_hash = b'\xda' * 32
-    current_version = spec.GENESIS_FORK_VERSION
+    current_version = spec.config.GENESIS_FORK_VERSION
 
     if spec.fork == ALTAIR:
-        current_version = spec.ALTAIR_FORK_VERSION
+        current_version = spec.config.ALTAIR_FORK_VERSION
     elif spec.fork == MERGE:
-        current_version = spec.MERGE_FORK_VERSION
+        current_version = spec.config.MERGE_FORK_VERSION
 
     state = spec.BeaconState(
         genesis_time=0,
@@ -41,7 +41,7 @@ def create_genesis_state(spec, validator_balances, activation_threshold):
             block_hash=eth1_block_hash,
         ),
         fork=spec.Fork(
-            previous_version=spec.GENESIS_FORK_VERSION,
+            previous_version=spec.config.GENESIS_FORK_VERSION,
             current_version=current_version,
             epoch=spec.GENESIS_EPOCH,
         ),
diff --git a/tests/core/pyspec/eth2spec/test/helpers/multi_operations.py b/tests/core/pyspec/eth2spec/test/helpers/multi_operations.py
index 89ac95a3e..4b6c9b25d 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/multi_operations.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/multi_operations.py
@@ -19,7 +19,7 @@ def run_slash_and_exit(spec, state, slash_index, exit_index, valid=True):
     Helper function to run a test that slashes and exits two validators
     """
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     yield 'pre', state
 
@@ -127,7 +127,7 @@ def get_random_voluntary_exits(spec, state, to_be_slashed_indices, rng):
 
 def run_test_full_random_operations(spec, state, rng=Random(2080)):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     # prepare state for deposits before building block
     deposits = prepare_state_and_get_random_deposits(spec, state, rng)
diff --git a/tests/core/pyspec/eth2spec/test/helpers/rewards.py b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
index 86bb70133..fefa19886 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/rewards.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
@@ -45,7 +45,7 @@ def has_enough_for_leak_penalty(spec, state, index):
     if is_post_altair(spec):
         return (
             state.validators[index].effective_balance * state.inactivity_scores[index]
-            > spec.INACTIVITY_SCORE_BIAS * spec.INACTIVITY_PENALTY_QUOTIENT_ALTAIR
+            > spec.config.INACTIVITY_SCORE_BIAS * spec.INACTIVITY_PENALTY_QUOTIENT_ALTAIR
         )
     else:
         return (
diff --git a/tests/core/pyspec/eth2spec/test/helpers/state.py b/tests/core/pyspec/eth2spec/test/helpers/state.py
index d61df7610..74521087d 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/state.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/state.py
@@ -42,10 +42,10 @@ def transition_to_slot_via_block(spec, state, slot):
 
 def transition_to_valid_shard_slot(spec, state):
     """
-    Transition to slot `compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH) + 1`
-    and fork at `compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH)`.
+    Transition to slot `compute_epoch_at_slot(spec.config.SHARDING_FORK_EPOCH) + 1`
+    and fork at `compute_epoch_at_slot(spec.config.SHARDING_FORK_EPOCH)`.
     """
-    transition_to(spec, state, spec.compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH))
+    transition_to(spec, state, spec.compute_epoch_at_slot(spec.config.SHARDING_FORK_EPOCH))
     next_slot(spec, state)
 
 
diff --git a/tests/core/pyspec/eth2spec/test/phase0/block_processing/test_process_voluntary_exit.py b/tests/core/pyspec/eth2spec/test/phase0/block_processing/test_process_voluntary_exit.py
index 9464f80aa..f713d1792 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/block_processing/test_process_voluntary_exit.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/block_processing/test_process_voluntary_exit.py
@@ -35,7 +35,7 @@ def run_voluntary_exit_processing(spec, state, signed_voluntary_exit, valid=True
 @spec_state_test
 def test_success(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -54,7 +54,7 @@ def test_success(spec, state):
 @always_bls
 def test_invalid_signature(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -72,7 +72,7 @@ def test_invalid_signature(spec, state):
 @spec_state_test
 def test_success_exit_queue(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
 
@@ -116,7 +116,7 @@ def test_success_exit_queue(spec, state):
 @spec_state_test
 def test_default_exit_epoch_subsequent_exit(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -138,7 +138,7 @@ def test_default_exit_epoch_subsequent_exit(spec, state):
 @spec_state_test
 def test_validator_exit_in_future(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -157,7 +157,7 @@ def test_validator_exit_in_future(spec, state):
 @spec_state_test
 def test_validator_invalid_validator_index(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -191,7 +191,7 @@ def test_validator_not_active(spec, state):
 @spec_state_test
 def test_validator_already_exited(spec, state):
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow validator able to exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     current_epoch = spec.get_current_epoch(state)
     validator_index = spec.get_active_validator_indices(state, current_epoch)[0]
@@ -218,7 +218,7 @@ def test_validator_not_active_long_enough(spec, state):
 
     assert (
         current_epoch - state.validators[validator_index].activation_epoch <
-        spec.SHARD_COMMITTEE_PERIOD
+        spec.config.SHARD_COMMITTEE_PERIOD
     )
 
     yield from run_voluntary_exit_processing(spec, state, signed_voluntary_exit, False)
diff --git a/tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_rewards_and_penalties.py b/tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_rewards_and_penalties.py
index 9abcff57e..7ff4e83d3 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_rewards_and_penalties.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_rewards_and_penalties.py
@@ -423,7 +423,7 @@ def test_attestations_some_slashed(spec, state):
     attesting_indices_before_slashings = list(spec.get_unslashed_attesting_indices(state, attestations))
 
     # Slash maximum amount of validators allowed per epoch.
-    for i in range(spec.MIN_PER_EPOCH_CHURN_LIMIT):
+    for i in range(spec.config.MIN_PER_EPOCH_CHURN_LIMIT):
         spec.slash_validator(state, attesting_indices_before_slashings[i])
 
     if not is_post_altair(spec):
@@ -435,5 +435,5 @@ def test_attestations_some_slashed(spec, state):
 
     attesting_indices = spec.get_unslashed_attesting_indices(state, attestations)
     assert len(attesting_indices) > 0
-    assert len(attesting_indices_before_slashings) - len(attesting_indices) == spec.MIN_PER_EPOCH_CHURN_LIMIT
+    assert len(attesting_indices_before_slashings) - len(attesting_indices) == spec.config.MIN_PER_EPOCH_CHURN_LIMIT
     validate_resulting_balances(spec, pre_state, state, attestations)
diff --git a/tests/core/pyspec/eth2spec/test/phase0/fork_choice/test_get_head.py b/tests/core/pyspec/eth2spec/test/phase0/fork_choice/test_get_head.py
index fae1c5ae2..bce886931 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/fork_choice/test_get_head.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/fork_choice/test_get_head.py
@@ -197,7 +197,7 @@ def test_filtered_block_tree(spec, state):
     assert state.current_justified_checkpoint.epoch > prev_state.current_justified_checkpoint.epoch
 
     # tick time forward and add blocks and attestations to store
-    current_time = state.slot * spec.SECONDS_PER_SLOT + store.genesis_time
+    current_time = state.slot * spec.config.SECONDS_PER_SLOT + store.genesis_time
     on_tick_and_append_step(spec, store, current_time, test_steps)
     for signed_block in signed_blocks:
         yield from run_on_block(spec, store, signed_block, test_steps)
@@ -243,7 +243,7 @@ def test_filtered_block_tree(spec, state):
             attestations.append(attestation)
 
     # tick time forward to be able to include up to the latest attestation
-    current_time = (attestations[-1].data.slot + 1) * spec.SECONDS_PER_SLOT + store.genesis_time
+    current_time = (attestations[-1].data.slot + 1) * spec.config.SECONDS_PER_SLOT + store.genesis_time
     on_tick_and_append_step(spec, store, current_time, test_steps)
 
     # include rogue block and associated attestations in the store
diff --git a/tests/core/pyspec/eth2spec/test/phase0/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/phase0/sanity/test_blocks.py
index 8aab1e9ee..117ce1947 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/sanity/test_blocks.py
@@ -814,7 +814,7 @@ def test_voluntary_exit(spec, state):
     validator_index = spec.get_active_validator_indices(state, spec.get_current_epoch(state))[-1]
 
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     signed_exits = prepare_signed_exits(spec, state, [validator_index])
     yield 'pre', state
@@ -842,7 +842,7 @@ def test_double_validator_exit_same_block(spec, state):
     validator_index = spec.get_active_validator_indices(state, spec.get_current_epoch(state))[-1]
 
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     # Same index tries to exit twice, but should only be able to do so once.
     signed_exits = prepare_signed_exits(spec, state, [validator_index, validator_index])
@@ -866,7 +866,7 @@ def test_multiple_different_validator_exits_same_block(spec, state):
         for i in range(3)
     ]
     # move state forward SHARD_COMMITTEE_PERIOD epochs to allow for exit
-    state.slot += spec.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
+    state.slot += spec.config.SHARD_COMMITTEE_PERIOD * spec.SLOTS_PER_EPOCH
 
     signed_exits = prepare_signed_exits(spec, state, validator_indices)
     yield 'pre', state
diff --git a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
index 8ff6bbb38..9007a778f 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
@@ -35,7 +35,7 @@ def run_on_attestation(spec, state, store, attestation, valid=True):
 @spec_state_test
 def test_on_attestation_current_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    spec.on_tick(store, store.time + spec.SECONDS_PER_SLOT * 2)
+    spec.on_tick(store, store.time + spec.config.SECONDS_PER_SLOT * 2)
 
     block = build_empty_block_for_next_slot(spec, state)
     signed_block = state_transition_and_sign_block(spec, state, block)
@@ -54,7 +54,7 @@ def test_on_attestation_current_epoch(spec, state):
 @spec_state_test
 def test_on_attestation_previous_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    spec.on_tick(store, store.time + spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
+    spec.on_tick(store, store.time + spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
 
     block = build_empty_block_for_next_slot(spec, state)
     signed_block = state_transition_and_sign_block(spec, state, block)
@@ -75,7 +75,7 @@ def test_on_attestation_past_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
 
     # move time forward 2 epochs
-    time = store.time + 2 * spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    time = store.time + 2 * spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
     spec.on_tick(store, time)
 
     # create and store block from 3 epochs ago
@@ -95,7 +95,7 @@ def test_on_attestation_past_epoch(spec, state):
 @spec_state_test
 def test_on_attestation_mismatched_target_and_slot(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    spec.on_tick(store, store.time + spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
+    spec.on_tick(store, store.time + spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
 
     block = build_empty_block_for_next_slot(spec, state)
     signed_block = state_transition_and_sign_block(spec, state, block)
@@ -118,7 +118,7 @@ def test_on_attestation_mismatched_target_and_slot(spec, state):
 @spec_state_test
 def test_on_attestation_inconsistent_target_and_head(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    spec.on_tick(store, store.time + 2 * spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
+    spec.on_tick(store, store.time + 2 * spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
 
     # Create chain 1 as empty chain between genesis and start of 1st epoch
     target_state_1 = state.copy()
@@ -156,7 +156,7 @@ def test_on_attestation_inconsistent_target_and_head(spec, state):
 @spec_state_test
 def test_on_attestation_target_block_not_in_store(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
+    time = store.time + spec.config.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
     spec.on_tick(store, time)
 
     # move to immediately before next epoch to make block new target
@@ -178,7 +178,7 @@ def test_on_attestation_target_block_not_in_store(spec, state):
 @spec_state_test
 def test_on_attestation_target_checkpoint_not_in_store(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
+    time = store.time + spec.config.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
     spec.on_tick(store, time)
 
     # move to immediately before next epoch to make block new target
@@ -203,7 +203,7 @@ def test_on_attestation_target_checkpoint_not_in_store(spec, state):
 @spec_state_test
 def test_on_attestation_target_checkpoint_not_in_store_diff_slot(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
+    time = store.time + spec.config.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
     spec.on_tick(store, time)
 
     # move to two slots before next epoch to make target block one before an empty slot
@@ -230,7 +230,7 @@ def test_on_attestation_target_checkpoint_not_in_store_diff_slot(spec, state):
 @spec_state_test
 def test_on_attestation_beacon_block_not_in_store(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
+    time = store.time + spec.config.SECONDS_PER_SLOT * (spec.SLOTS_PER_EPOCH + 1)
     spec.on_tick(store, time)
 
     # move to immediately before next epoch to make block new target
@@ -259,7 +259,7 @@ def test_on_attestation_beacon_block_not_in_store(spec, state):
 @spec_state_test
 def test_on_attestation_future_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + 3 * spec.SECONDS_PER_SLOT
+    time = store.time + 3 * spec.config.SECONDS_PER_SLOT
     spec.on_tick(store, time)
 
     block = build_empty_block_for_next_slot(spec, state)
@@ -279,7 +279,7 @@ def test_on_attestation_future_epoch(spec, state):
 @spec_state_test
 def test_on_attestation_future_block(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT * 5
+    time = store.time + spec.config.SECONDS_PER_SLOT * 5
     spec.on_tick(store, time)
 
     block = build_empty_block_for_next_slot(spec, state)
@@ -299,7 +299,7 @@ def test_on_attestation_future_block(spec, state):
 @spec_state_test
 def test_on_attestation_same_slot(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + spec.SECONDS_PER_SLOT
+    time = store.time + spec.config.SECONDS_PER_SLOT
     spec.on_tick(store, time)
 
     block = build_empty_block_for_next_slot(spec, state)
@@ -315,7 +315,7 @@ def test_on_attestation_same_slot(spec, state):
 @spec_state_test
 def test_on_attestation_invalid_attestation(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    time = store.time + 3 * spec.SECONDS_PER_SLOT
+    time = store.time + 3 * spec.config.SECONDS_PER_SLOT
     spec.on_tick(store, time)
 
     block = build_empty_block_for_next_slot(spec, state)
diff --git a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_block.py b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_block.py
index 48ea78e39..b1862d093 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_block.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_block.py
@@ -30,7 +30,7 @@ def apply_next_epoch_with_attestations(spec, state, store):
         store.blocks[block_root] = block
         store.block_states[block_root] = post_state
         last_signed_block = signed_block
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     return post_state, store, last_signed_block
 
 
@@ -49,7 +49,7 @@ def test_basic(spec, state):
     run_on_block(spec, store, signed_block)
 
     # On receiving a block of next epoch
-    store.time = time + spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    store.time = time + spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
     block = build_empty_block(spec, state, state.slot + spec.SLOTS_PER_EPOCH)
     signed_block = state_transition_and_sign_block(spec, state, block)
 
@@ -67,10 +67,10 @@ def test_on_block_checkpoints(spec, state):
     spec.on_tick(store, time)
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     state, store, last_signed_block = apply_next_epoch_with_attestations(spec, state, store)
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     last_block_root = hash_tree_root(last_signed_block.message)
 
     # Mock the finalized_checkpoint
@@ -153,7 +153,7 @@ def test_on_block_finalized_skip_slots(spec, state):
     # Build block that includes the skipped slots up to finality in chain
     block = build_empty_block(spec, state, spec.compute_start_slot_at_epoch(store.finalized_checkpoint.epoch) + 2)
     signed_block = state_transition_and_sign_block(spec, state, block)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     run_on_block(spec, store, signed_block)
 
 
@@ -178,7 +178,7 @@ def test_on_block_finalized_skip_slots_not_in_skip_chain(spec, state):
     # Includes finalized block in chain, but not at appropriate skip slot
     block = build_empty_block(spec, state, spec.compute_start_slot_at_epoch(store.finalized_checkpoint.epoch) + 2)
     signed_block = state_transition_and_sign_block(spec, state, block)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     run_on_block(spec, store, signed_block, False)
 
 
@@ -191,10 +191,10 @@ def test_on_block_update_justified_checkpoint_within_safe_slots(spec, state):
     spec.on_tick(store, time)
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     state, store, last_signed_block = apply_next_epoch_with_attestations(spec, state, store)
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     last_block_root = hash_tree_root(last_signed_block.message)
 
     # Mock the justified checkpoint
@@ -222,7 +222,7 @@ def test_on_block_outside_safe_slots_and_multiple_better_justified(spec, state):
     spec.on_tick(store, time)
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     state, store, last_signed_block = apply_next_epoch_with_attestations(spec, state, store)
     last_block_root = hash_tree_root(last_signed_block.message)
 
@@ -233,14 +233,14 @@ def test_on_block_outside_safe_slots_and_multiple_better_justified(spec, state):
     )
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
 
     # Create new higher justified checkpoint not in branch of store's justified checkpoint
     just_block = build_empty_block_for_next_slot(spec, state)
     store.blocks[just_block.hash_tree_root()] = just_block
 
     # Step time past safe slots
-    spec.on_tick(store, store.time + spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED * spec.config.SECONDS_PER_SLOT)
     assert spec.get_current_slot(store) % spec.SLOTS_PER_EPOCH >= spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED
 
     previously_justified = store.justified_checkpoint
@@ -277,7 +277,7 @@ def test_on_block_outside_safe_slots_but_finality(spec, state):
     spec.on_tick(store, time)
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
     state, store, last_signed_block = apply_next_epoch_with_attestations(spec, state, store)
     last_block_root = hash_tree_root(last_signed_block.message)
 
@@ -288,14 +288,14 @@ def test_on_block_outside_safe_slots_but_finality(spec, state):
     )
 
     next_epoch(spec, state)
-    spec.on_tick(store, store.time + state.slot * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + state.slot * spec.config.SECONDS_PER_SLOT)
 
     # Create new higher justified checkpoint not in branch of store's justified checkpoint
     just_block = build_empty_block_for_next_slot(spec, state)
     store.blocks[just_block.hash_tree_root()] = just_block
 
     # Step time past safe slots
-    spec.on_tick(store, store.time + spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED * spec.SECONDS_PER_SLOT)
+    spec.on_tick(store, store.time + spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED * spec.config.SECONDS_PER_SLOT)
     assert spec.get_current_slot(store) % spec.SLOTS_PER_EPOCH >= spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED
 
     # Mock justified and finalized update in state
diff --git a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_tick.py b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_tick.py
index 9cf0e9e26..ef643fd6b 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_tick.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_tick.py
@@ -30,7 +30,7 @@ def test_update_justified_single(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
     next_epoch = spec.get_current_epoch(state) + 1
     next_epoch_start_slot = spec.compute_start_slot_at_epoch(next_epoch)
-    seconds_until_next_epoch = next_epoch_start_slot * spec.SECONDS_PER_SLOT - store.time
+    seconds_until_next_epoch = next_epoch_start_slot * spec.config.SECONDS_PER_SLOT - store.time
 
     store.best_justified_checkpoint = spec.Checkpoint(
         epoch=store.justified_checkpoint.epoch + 1,
@@ -44,7 +44,7 @@ def test_update_justified_single(spec, state):
 @spec_state_test
 def test_no_update_same_slot_at_epoch_boundary(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    seconds_per_epoch = spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    seconds_per_epoch = spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
 
     store.best_justified_checkpoint = spec.Checkpoint(
         epoch=store.justified_checkpoint.epoch + 1,
@@ -67,14 +67,14 @@ def test_no_update_not_epoch_boundary(spec, state):
         root=b'\x55' * 32,
     )
 
-    run_on_tick(spec, store, store.time + spec.SECONDS_PER_SLOT)
+    run_on_tick(spec, store, store.time + spec.config.SECONDS_PER_SLOT)
 
 
 @with_all_phases
 @spec_state_test
 def test_no_update_new_justified_equal_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    seconds_per_epoch = spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    seconds_per_epoch = spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
 
     store.best_justified_checkpoint = spec.Checkpoint(
         epoch=store.justified_checkpoint.epoch + 1,
@@ -93,7 +93,7 @@ def test_no_update_new_justified_equal_epoch(spec, state):
 @spec_state_test
 def test_no_update_new_justified_later_epoch(spec, state):
     store = get_genesis_forkchoice_store(spec, state)
-    seconds_per_epoch = spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    seconds_per_epoch = spec.config.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
 
     store.best_justified_checkpoint = spec.Checkpoint(
         epoch=store.justified_checkpoint.epoch + 1,
diff --git a/tests/core/pyspec/eth2spec/test/phase0/unittests/validator/test_validator_unittest.py b/tests/core/pyspec/eth2spec/test/phase0/unittests/validator/test_validator_unittest.py
index fb63839d6..23d6d78ee 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/unittests/validator/test_validator_unittest.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/unittests/validator/test_validator_unittest.py
@@ -41,8 +41,8 @@ def run_is_candidate_block(spec, eth1_block, period_start, success=True):
 
 def get_min_new_period_epochs(spec):
     return (
-        (spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE * 2)  # to seconds
-        // spec.SECONDS_PER_SLOT // spec.SLOTS_PER_EPOCH
+        (spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE * 2)  # to seconds
+        // spec.config.SECONDS_PER_SLOT // spec.SLOTS_PER_EPOCH
     )
 
 
@@ -140,28 +140,28 @@ def test_get_epoch_signature(spec, state):
 @with_all_phases
 @spec_state_test
 def test_is_candidate_block(spec, state):
-    period_start = spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE * 2 + 1000
+    period_start = spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE * 2 + 1000
     run_is_candidate_block(
         spec,
-        spec.Eth1Block(timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE),
+        spec.Eth1Block(timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE),
         period_start,
         success=True,
     )
     run_is_candidate_block(
         spec,
-        spec.Eth1Block(timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE + 1),
+        spec.Eth1Block(timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE + 1),
         period_start,
         success=False,
     )
     run_is_candidate_block(
         spec,
-        spec.Eth1Block(timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE * 2),
+        spec.Eth1Block(timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE * 2),
         period_start,
         success=True,
     )
     run_is_candidate_block(
         spec,
-        spec.Eth1Block(timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE * 2 - 1),
+        spec.Eth1Block(timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE * 2 - 1),
         period_start,
         success=False,
     )
@@ -193,12 +193,12 @@ def test_get_eth1_vote_consensus_vote(spec, state):
     state.eth1_data_votes = ()
 
     block_1 = spec.Eth1Block(
-        timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE - 1,
+        timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE - 1,
         deposit_count=state.eth1_data.deposit_count,
         deposit_root=b'\x04' * 32,
     )
     block_2 = spec.Eth1Block(
-        timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE,
+        timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE,
         deposit_count=state.eth1_data.deposit_count + 1,
         deposit_root=b'\x05' * 32,
     )
@@ -229,12 +229,12 @@ def test_get_eth1_vote_tie(spec, state):
 
     state.eth1_data_votes = ()
     block_1 = spec.Eth1Block(
-        timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE - 1,
+        timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE - 1,
         deposit_count=state.eth1_data.deposit_count,
         deposit_root=b'\x04' * 32,
     )
     block_2 = spec.Eth1Block(
-        timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE,
+        timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE,
         deposit_count=state.eth1_data.deposit_count + 1,
         deposit_root=b'\x05' * 32,
     )
@@ -268,7 +268,7 @@ def test_get_eth1_vote_chain_in_past(spec, state):
 
     state.eth1_data_votes = ()
     block_1 = spec.Eth1Block(
-        timestamp=period_start - spec.SECONDS_PER_ETH1_BLOCK * spec.ETH1_FOLLOW_DISTANCE,
+        timestamp=period_start - spec.config.SECONDS_PER_ETH1_BLOCK * spec.config.ETH1_FOLLOW_DISTANCE,
         deposit_count=state.eth1_data.deposit_count - 1,  # Chain prior to current eth1data
         deposit_root=b'\x42' * 32,
     )