fix transactions field in exec payload helper

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

@@ -18,7 +18,7 @@ def build_empty_execution_payload(spec, state):
         timestamp=timestamp,
         receipt_root=b"no receipts here" + b"\x00"*16,  # TODO: root of empty MPT may be better.
         logs_bloom=spec.ByteVector[spec.BYTES_PER_LOGS_BLOOM](),  # TODO: zeroed logs bloom for empty logs ok?
-        transactions_root=empty_txs,
+        transactions=empty_txs,
     )
     # TODO: real RLP + block hash logic would be nice, requires RLP and keccak256 dependency however.
     payload.block_hash = spec.Hash32(spec.hash(payload.hash_tree_root() + b"FAKE RLP HASH"))

tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py

@@ -1,4 +1,5 @@
 from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.test.helpers.execution_payload import build_empty_execution_payload
 from eth2spec.test.context import spec_state_test, expect_assertion_error, always_bls, with_all_phases_except
 
 with_merge_and_later = with_all_phases_except([PHASE0, ALTAIR])
@@ -36,7 +37,7 @@ def test_success_first_payload(spec, state):
     assert not spec.is_transition_completed(state)
 
     # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
+    execution_payload = build_empty_execution_payload(spec, state)
 
     yield from run_execution_payload_processing(spec, state, execution_payload)