Add basic activation churn limit tests

configs/mainnet.yaml

@@ -151,4 +151,4 @@ WHISK_EPOCHS_PER_SHUFFLING_PHASE: 256
 WHISK_PROPOSER_SELECTION_GAP: 2
 
 # EIP7668
-MAX_PER_EPOCH_INBOUND_CHURN_LIMIT: 12
+MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 12

configs/minimal.yaml

@@ -85,8 +85,8 @@ INACTIVITY_SCORE_BIAS: 4
 INACTIVITY_SCORE_RECOVERY_RATE: 16
 # 2**4 * 10**9 (= 16,000,000,000) Gwei
 EJECTION_BALANCE: 16000000000
-# 2**2 (= 4)
-MIN_PER_EPOCH_CHURN_LIMIT: 4
+# [customized]
+MIN_PER_EPOCH_CHURN_LIMIT: 2
 # [customized] scale queue churn at much lower validator counts for testing
 CHURN_LIMIT_QUOTIENT: 32
 
@@ -150,4 +150,5 @@ WHISK_EPOCHS_PER_SHUFFLING_PHASE: 4
 WHISK_PROPOSER_SELECTION_GAP: 1
 
 # EIP7668
-MAX_PER_EPOCH_INBOUND_CHURN_LIMIT: 12
+# [customized]
+MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT: 4

specs/_features/eip7668/beacon_chain.md

@@ -44,7 +44,7 @@ def get_validator_activation_churn_limit(state: BeaconState) -> uint64:
     """
     Return the validator activation churn limit for the current epoch.
     """
-    return min(MAX_PER_EPOCH_INBOUND_CHURN_LIMIT, get_validator_churn_limit(state))
+    return min(MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT, get_validator_churn_limit(state))
 ```
 
 ## Beacon chain state transition function

tests/core/pyspec/eth2spec/test/context.py

@@ -165,14 +165,34 @@ def default_balances(spec: Spec):
     return [spec.MAX_EFFECTIVE_BALANCE] * num_validators
 
 
-def scaled_churn_balances(spec: Spec):
+def scaled_churn_balances_min_churn_limit(spec: Spec):
     """
     Helper method to create enough validators to scale the churn limit.
     (This is *firmly* over the churn limit -- thus the +2 instead of just +1)
     See the second argument of ``max`` in ``get_validator_churn_limit``.
-    Usage: `@with_custom_state(balances_fn=scaled_churn_balances, ...)`
+    Usage: `@with_custom_state(balances_fn=scaled_churn_balances_min_churn_limit, ...)`
     """
-    num_validators = spec.config.CHURN_LIMIT_QUOTIENT * (2 + spec.config.MIN_PER_EPOCH_CHURN_LIMIT)
+    num_validators = spec.config.CHURN_LIMIT_QUOTIENT * (spec.config.MIN_PER_EPOCH_CHURN_LIMIT + 2)
+    return [spec.MAX_EFFECTIVE_BALANCE] * num_validators
+
+
+def scaled_churn_balances_equal_inbound_churn_limit(spec: Spec):
+    """
+    Helper method to create enough validators to scale the churn limit.
+    (This is *firmly* over the churn limit -- thus the +2 instead of just +1)
+    Usage: `@with_custom_state(balances_fn=scaled_churn_balances_exceed_inbound_churn_limit, ...)`
+    """
+    num_validators = spec.config.CHURN_LIMIT_QUOTIENT * (spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT)
+    return [spec.MAX_EFFECTIVE_BALANCE] * num_validators
+
+
+def scaled_churn_balances_exceed_inbound_churn_limit(spec: Spec):
+    """
+    Helper method to create enough validators to scale the churn limit.
+    (This is *firmly* over the churn limit -- thus the +2 instead of just +1)
+    Usage: `@with_custom_state(balances_fn=scaled_churn_balances_exceed_inbound_churn_limit, ...)`
+    """
+    num_validators = spec.config.CHURN_LIMIT_QUOTIENT * (spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT + 2)
     return [spec.MAX_EFFECTIVE_BALANCE] * num_validators
 
 
@@ -548,6 +568,7 @@ with_capella_and_later = with_all_phases_from(CAPELLA)
 with_deneb_and_later = with_all_phases_from(DENEB)
 with_eip6110_and_later = with_all_phases_from(EIP6110)
 with_eip7002_and_later = with_all_phases_from(EIP7002)
+with_eip7668_and_later = with_all_phases_from(EIP7668)
 
 
 class quoted_str(str):

tests/core/pyspec/eth2spec/test/eip7668/epoch_processing/test_process_registry_updates.py

@@ -0,0 +1,86 @@
+from eth2spec.test.helpers.keys import pubkeys
+from eth2spec.test.helpers.constants import MINIMAL
+from eth2spec.test.context import (
+    with_eip7668_and_later,
+    spec_test,
+    spec_state_test,
+    single_phase,
+    with_custom_state,
+    with_presets,
+    scaled_churn_balances_exceed_inbound_churn_limit,
+    scaled_churn_balances_equal_inbound_churn_limit,
+)
+from eth2spec.test.helpers.epoch_processing import run_epoch_processing_with
+
+
+def run_process_registry_updates(spec, state):
+    yield from run_epoch_processing_with(spec, state, 'process_registry_updates')
+
+
+def run_test_inbound_churn_limit(spec, state):
+    mock_activations = 1
+
+    for i in range(mock_activations):
+        index = len(state.validators) + i
+        validator = spec.Validator(
+            pubkey=pubkeys[index],
+            withdrawal_credentials=spec.ETH1_ADDRESS_WITHDRAWAL_PREFIX + b'\x00' * 11 + b'\x56' * 20,
+            activation_eligibility_epoch=0,
+            activation_epoch=spec.FAR_FUTURE_EPOCH,
+            exit_epoch=spec.FAR_FUTURE_EPOCH,
+            withdrawable_epoch=spec.FAR_FUTURE_EPOCH,
+            effective_balance=spec.MAX_EFFECTIVE_BALANCE,
+        )
+        state.validators.append(validator)
+        state.balances.append(spec.MAX_EFFECTIVE_BALANCE)
+        state.previous_epoch_participation.append(spec.ParticipationFlags(0b0000_0000))
+        state.current_epoch_participation.append(spec.ParticipationFlags(0b0000_0000))
+        state.inactivity_scores.append(0)
+        state.validators[index].activation_epoch = spec.FAR_FUTURE_EPOCH
+
+    churn_limit_0 = spec.get_validator_activation_churn_limit(state)
+
+    yield from run_process_registry_updates(spec, state)
+
+    # Half should churn in first run of registry update
+    for i in range(mock_activations):
+        if i < churn_limit_0:
+            assert state.validators[i].activation_epoch < spec.FAR_FUTURE_EPOCH
+        else:
+            assert state.validators[i].activation_epoch == spec.FAR_FUTURE_EPOCH
+
+
+@with_eip7668_and_later
+@with_presets([MINIMAL],
+              reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
+@spec_test
+@with_custom_state(balances_fn=scaled_churn_balances_exceed_inbound_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@single_phase
+def test_inbound_churn_limit__greater_than_inbound_limit(spec, state):
+    assert spec.get_validator_activation_churn_limit(state) == spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    assert spec.get_validator_churn_limit(state) > spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    yield from run_test_inbound_churn_limit(spec, state)
+
+
+@with_eip7668_and_later
+@with_presets([MINIMAL],
+              reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
+@spec_test
+@with_custom_state(balances_fn=scaled_churn_balances_equal_inbound_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@single_phase
+def test_inbound_churn_limit__equal_to_inbound_limit(spec, state):
+    assert spec.get_validator_activation_churn_limit(state) == spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    assert spec.get_validator_churn_limit(state) == spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    yield from run_test_inbound_churn_limit(spec, state)
+
+
+@with_eip7668_and_later
+@with_presets([MINIMAL],
+              reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
+@spec_state_test
+def test_inbound_churn_limit__less_than_inbound_limit(spec, state):
+    assert spec.get_validator_activation_churn_limit(state) < spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    assert spec.get_validator_churn_limit(state) < spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    yield from run_test_inbound_churn_limit(spec, state)

tests/core/pyspec/eth2spec/test/helpers/forks.py

@@ -46,3 +46,7 @@ def is_post_eip6110(spec):
 
 def is_post_eip7002(spec):
     return is_post_fork(spec.fork, EIP7002)
+
+
+def is_post_eip7668(spec):
+    return is_post_fork(spec.fork, EIP7668)

tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_registry_updates.py

@@ -5,7 +5,7 @@ from eth2spec.test.context import (
     spec_test, spec_state_test,
     with_all_phases, single_phase,
     with_custom_state, with_presets,
-    scaled_churn_balances,
+    scaled_churn_balances_min_churn_limit,
 )
 from eth2spec.test.helpers.epoch_processing import run_epoch_processing_with
 
@@ -164,7 +164,8 @@ def test_activation_queue_efficiency_min(spec, state):
 @with_presets([MINIMAL],
               reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
 @spec_test
-@with_custom_state(balances_fn=scaled_churn_balances, threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@with_custom_state(balances_fn=scaled_churn_balances_min_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
 @single_phase
 def test_activation_queue_efficiency_scaled(spec, state):
     assert spec.get_validator_churn_limit(state) > spec.config.MIN_PER_EPOCH_CHURN_LIMIT
@@ -227,7 +228,8 @@ def test_ejection_past_churn_limit_min(spec, state):
 @with_presets([MINIMAL],
               reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
 @spec_test
-@with_custom_state(balances_fn=scaled_churn_balances, threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@with_custom_state(balances_fn=scaled_churn_balances_min_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
 @single_phase
 def test_ejection_past_churn_limit_scaled(spec, state):
     assert spec.get_validator_churn_limit(state) > spec.config.MIN_PER_EPOCH_CHURN_LIMIT
@@ -324,7 +326,8 @@ def test_activation_queue_activation_and_ejection__exceed_churn_limit(spec, stat
 @with_presets([MINIMAL],
               reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
 @spec_test
-@with_custom_state(balances_fn=scaled_churn_balances, threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@with_custom_state(balances_fn=scaled_churn_balances_min_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
 @single_phase
 def test_activation_queue_activation_and_ejection__scaled_churn_limit(spec, state):
     churn_limit = spec.get_validator_churn_limit(state)
@@ -336,7 +339,8 @@ def test_activation_queue_activation_and_ejection__scaled_churn_limit(spec, stat
 @with_presets([MINIMAL],
               reason="mainnet config leads to larger validator set than limit of public/private keys pre-generated")
 @spec_test
-@with_custom_state(balances_fn=scaled_churn_balances, threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
+@with_custom_state(balances_fn=scaled_churn_balances_min_churn_limit,
+                   threshold_fn=lambda spec: spec.config.EJECTION_BALANCE)
 @single_phase
 def test_activation_queue_activation_and_ejection__exceed_scaled_churn_limit(spec, state):
     churn_limit = spec.get_validator_churn_limit(state)