diff --git a/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py b/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
index aaaf5c23b..b26417e8f 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/fork_choice.py
@@ -1,3 +1,4 @@
+from random import Random
 from eth_utils import encode_hex
 from eth2spec.utils.ssz.ssz_typing import uint256
 from eth2spec.test.helpers.attestations import (
@@ -23,9 +24,12 @@ def add_block_to_store(spec, store, signed_block):
     spec.on_block(store, signed_block)
 
 
-def tick_and_add_block(spec, store, signed_block, test_steps, valid=True, allow_invalid_attestations=False):
+def tick_and_add_block(spec, store, signed_block, test_steps, valid=True, allow_invalid_attestations=False,
+                       merge_block=False):
     pre_state = store.block_states[signed_block.message.parent_root]
     block_time = pre_state.genesis_time + signed_block.message.slot * spec.config.SECONDS_PER_SLOT
+    if merge_block:
+        assert spec.is_merge_block(pre_state, signed_block.message.body)
 
     if store.time < block_time:
         on_tick_and_append_step(spec, store, block_time, test_steps)
@@ -230,10 +234,10 @@ def apply_next_slots_with_attestations(spec,
     return post_state, store, last_signed_block
 
 
-def prepare_empty_pow_block(spec):
+def prepare_empty_pow_block(spec, rng=Random(3131)):
     return spec.PowBlock(
-        block_hash=spec.Hash32(),
-        parent_hash=spec.Hash32(),
+        block_hash=spec.Hash32(spec.hash(rng.randbytes(32))),
+        parent_hash=spec.Hash32(spec.hash(rng.randbytes(32))),
         total_difficulty=uint256(0),
         difficulty=uint256(0)
     )
diff --git a/tests/core/pyspec/eth2spec/test/merge/unittests/test_terminal_validity.py b/tests/core/pyspec/eth2spec/test/merge/unittests/test_terminal_validity.py
index 6c2a623b2..42d83b4a0 100644
--- a/tests/core/pyspec/eth2spec/test/merge/unittests/test_terminal_validity.py
+++ b/tests/core/pyspec/eth2spec/test/merge/unittests/test_terminal_validity.py
@@ -102,7 +102,6 @@ def test_valid_terminal_pow_block_fail_just_after_terminal(spec, state):
 @spec_state_test
 def test_process_merge_execution_payload_success(spec, state):
     parent_block = prepare_empty_pow_block(spec)
-    parent_block.block_hash = spec.Hash32(spec.hash(b'01'))
     parent_block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY - uint256(1)
     block = prepare_empty_pow_block(spec)
     block.parent_hash = parent_block.block_hash
@@ -116,13 +115,11 @@ def test_process_merge_execution_payload_success(spec, state):
 @spec_state_test
 def test_process_merge_execution_payload_fail_block_lookup(spec, state):
     parent_block = prepare_empty_pow_block(spec)
-    parent_block.block_hash = spec.Hash32(spec.hash(b'01'))
     parent_block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY - uint256(1)
     block = prepare_empty_pow_block(spec)
     block.parent_hash = parent_block.block_hash
     block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY
     payload = spec.ExecutionPayload()
-    payload.parent_hash = spec.Hash32(spec.hash(b'02'))
     yield from run_process_merge_execution_payload(spec, block, parent_block, payload,
                                                    block_lookup_success=False)
 
@@ -131,10 +128,8 @@ def test_process_merge_execution_payload_fail_block_lookup(spec, state):
 @spec_state_test
 def test_process_merge_execution_payload_fail_parent_block_lookup(spec, state):
     parent_block = prepare_empty_pow_block(spec)
-    parent_block.block_hash = spec.Hash32(spec.hash(b'01'))
     parent_block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY - uint256(1)
     block = prepare_empty_pow_block(spec)
-    block.parent_hash = spec.Hash32(spec.hash(b'00'))
     block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY
     payload = spec.ExecutionPayload()
     payload.parent_hash = block.block_hash
@@ -146,7 +141,6 @@ def test_process_merge_execution_payload_fail_parent_block_lookup(spec, state):
 @spec_state_test
 def test_process_merge_execution_payload_fail_after_terminal(spec, state):
     parent_block = prepare_empty_pow_block(spec)
-    parent_block.block_hash = spec.Hash32(spec.hash(b'01'))
     parent_block.total_difficulty = spec.config.TERMINAL_TOTAL_DIFFICULTY
     block = prepare_empty_pow_block(spec)
     block.parent_hash = parent_block.block_hash