From f020649519eae4d3f2fa70a15c294cdf4cbfdd7d Mon Sep 17 00:00:00 2001
From: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
Date: Thu, 15 Feb 2024 00:19:27 +0800
Subject: [PATCH] add higher_churn_limit_to_lower tests

---
 .../test/deneb/transition/test_transition.py  | 112 ++++++++++++++++++
 tests/generators/transition/main.py           |   2 +
 2 files changed, 114 insertions(+)
 create mode 100644 tests/core/pyspec/eth2spec/test/deneb/transition/test_transition.py

diff --git a/tests/core/pyspec/eth2spec/test/deneb/transition/test_transition.py b/tests/core/pyspec/eth2spec/test/deneb/transition/test_transition.py
new file mode 100644
index 000000000..04a419c13
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/deneb/transition/test_transition.py
@@ -0,0 +1,112 @@
+from eth2spec.test.context import (
+    ForkMeta,
+    with_fork_metas,
+    with_presets,
+)
+from eth2spec.test.helpers.constants import (
+    AFTER_DENEB_PRE_POST_FORKS,
+    MINIMAL,
+)
+from eth2spec.test.helpers.keys import pubkeys
+from eth2spec.test.helpers.fork_transition import (
+    do_fork,
+    transition_to_next_epoch_and_append_blocks,
+    transition_until_fork,
+)
+
+
+def mock_activated_validators(spec, state, mock_activations):
+    validator_count = len(state.validators)
+    for i in range(mock_activations):
+        index = validator_count + 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.get_current_epoch(state)
+
+
+@with_fork_metas([ForkMeta(pre_fork_name=pre, post_fork_name=post, fork_epoch=2)
+                  for pre, post in AFTER_DENEB_PRE_POST_FORKS])
+@with_presets([MINIMAL], reason="churn limit update needs enough validators")
+def test_higher_churn_limit_to_lower(state, fork_epoch, spec, post_spec, pre_tag, post_tag):
+    """
+    Test if churn limit goes from high to low due to EIP-7514.
+    """
+    # Create high churn limit
+    mock_activations = post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT * spec.config.CHURN_LIMIT_QUOTIENT
+    mock_activated_validators(spec, state, mock_activations)
+
+    transition_until_fork(spec, state, fork_epoch)
+
+    churn_limit_0 = spec.get_validator_churn_limit(state)
+    assert churn_limit_0 > post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+
+    # check pre state
+    assert spec.get_current_epoch(state) < fork_epoch
+
+    yield "pre", state
+
+    # irregular state transition to handle fork
+    blocks = []
+    state, block = do_fork(state, spec, post_spec, fork_epoch)
+    blocks.append(post_tag(block))
+
+    # check post state
+    assert spec.get_current_epoch(state) == fork_epoch
+
+    # continue regular state transition with new spec into next epoch
+    transition_to_next_epoch_and_append_blocks(post_spec, state, post_tag, blocks, only_last_block=True)
+
+    yield "blocks", blocks
+    yield "post", state
+
+    churn_limit_1 = post_spec.get_validator_activation_churn_limit(state)
+    assert churn_limit_1 == post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    assert churn_limit_1 < churn_limit_0
+
+
+@with_fork_metas([ForkMeta(pre_fork_name=pre, post_fork_name=post, fork_epoch=2)
+                  for pre, post in AFTER_DENEB_PRE_POST_FORKS])
+@with_presets([MINIMAL], reason="churn limit update needs enough validators")
+def test_higher_churn_limit_to_lower__without_block(state, fork_epoch, spec, post_spec, pre_tag, post_tag):
+    """
+    Test if churn limit goes from high to low due to EIP-7514.
+    """
+    # Create high churn limit
+    mock_activations = post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT * spec.config.CHURN_LIMIT_QUOTIENT
+    mock_activated_validators(spec, state, mock_activations)
+
+    transition_until_fork(spec, state, fork_epoch)
+
+    churn_limit_0 = spec.get_validator_churn_limit(state)
+    assert churn_limit_0 > post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+
+    # check pre state
+    assert spec.get_current_epoch(state) < fork_epoch
+
+    yield "pre", state
+
+    # irregular state transition to handle fork
+    # set with_block=False here
+    state, _ = do_fork(state, spec, post_spec, fork_epoch, with_block=False)
+
+    # check post state
+    assert spec.get_current_epoch(state) == fork_epoch
+
+    yield "blocks", []
+    yield "post", state
+
+    churn_limit_1 = post_spec.get_validator_activation_churn_limit(state)
+    assert churn_limit_1 == post_spec.config.MAX_PER_EPOCH_ACTIVATION_CHURN_LIMIT
+    assert churn_limit_1 < churn_limit_0
diff --git a/tests/generators/transition/main.py b/tests/generators/transition/main.py
index 303f309c2..75ce72b28 100644
--- a/tests/generators/transition/main.py
+++ b/tests/generators/transition/main.py
@@ -18,6 +18,7 @@ from eth2spec.test.altair.transition import (
 )
 from eth2spec.test.deneb.transition import (
     test_operations as test_deneb_operations,
+    test_transition as test_deneb_transition,
 )
 
 
@@ -47,6 +48,7 @@ if __name__ == "__main__":
         test_altair_slashing,
         test_altair_operations,
         test_deneb_operations,
+        test_deneb_transition,
     )
     for transition_test_module in all_tests:
         for pre_fork, post_fork in ALL_PRE_POST_FORKS: