Add `test_fork_has_compounding_withdrawal_credential` test case

tests/core/pyspec/eth2spec/test/electra/fork/test_electra_fork_basic.py

@@ -80,3 +80,17 @@ def test_fork_random_misc_balances(spec, phases, state):
 @with_meta_tags(ELECTRA_FORK_TEST_META_TAGS)
 def test_fork_random_large_validator_set(spec, phases, state):
     yield from run_fork_test(phases[ELECTRA], state)
+
+
+@with_phases(phases=[DENEB], other_phases=[ELECTRA])
+@spec_test
+@with_state
+@with_meta_tags(ELECTRA_FORK_TEST_META_TAGS)
+def test_fork_has_compounding_withdrawal_credential(spec, phases, state):
+    post_spec = phases[ELECTRA]
+    validator = state.validators[0]
+    state.balances[0] = post_spec.MIN_ACTIVATION_BALANCE + 1
+    validator.withdrawal_credentials = post_spec.COMPOUNDING_WITHDRAWAL_PREFIX + validator.withdrawal_credentials[1:]
+    post_state = yield from run_fork_test(post_spec, state)
+
+    assert len(post_state.pending_balance_deposits) > 0

tests/core/pyspec/eth2spec/test/helpers/electra/fork.py

@@ -63,3 +63,5 @@ def run_fork_test(post_spec, pre_state):
     assert post_state.fork.epoch == post_spec.get_current_epoch(post_state)
 
     yield 'post', post_state
+
+    return post_state