From f37f9a367d4f55957ab70c59e6502993cf43ad3a Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 00:15:15 +0200
Subject: [PATCH 01/17] include merge in generators

---
 tests/generators/epoch_processing/main.py | 10 ++++++++--
 tests/generators/finality/main.py         |  9 ++++++---
 tests/generators/fork_choice/main.py      |  8 ++++++--
 tests/generators/operations/main.py       | 13 +++++++++++--
 tests/generators/rewards/main.py          | 11 +++++++++--
 tests/generators/sanity/main.py           | 11 +++++++++--
 tests/generators/ssz_static/main.py       |  2 +-
 7 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/tests/generators/epoch_processing/main.py b/tests/generators/epoch_processing/main.py
index 9efd96534b..2aa6381ffc 100644
--- a/tests/generators/epoch_processing/main.py
+++ b/tests/generators/epoch_processing/main.py
@@ -1,10 +1,11 @@
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
@@ -27,6 +28,10 @@
         **phase_0_mods,
     }  # also run the previous phase 0 tests
 
+    # No epoch-processing changes in Merge and previous testing repeats with new types, so no additional tests required.
+    # TODO: rebase onto Altair testing later.
+    merge_mods = phase_0_mods
+
     # TODO Custody Game testgen is disabled for now
     # custody_game_mods = {**{key: 'eth2spec.test.custody_game.epoch_processing.test_process_' + key for key in [
     #     'reveal_deadlines',
@@ -37,6 +42,7 @@
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: merge_mods,
     }
 
     run_state_test_generators(runner_name="epoch_processing", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/finality/main.py b/tests/generators/finality/main.py
index e50425da48..148ddef968 100644
--- a/tests/generators/finality/main.py
+++ b/tests/generators/finality/main.py
@@ -1,19 +1,22 @@
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
     phase_0_mods = {'finality': 'eth2spec.test.phase0.finality.test_finality'}
-    altair_mods = phase_0_mods   # No additional altair specific finality tests
+    altair_mods = phase_0_mods   # No additional Altair specific finality tests
+    merge_mods = phase_0_mods    # No additional Merge specific finality tests
 
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: spec_merge,
     }
 
     run_state_test_generators(runner_name="finality", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/fork_choice/main.py b/tests/generators/fork_choice/main.py
index 445ee629c3..ae15caa1d8 100644
--- a/tests/generators/fork_choice/main.py
+++ b/tests/generators/fork_choice/main.py
@@ -1,10 +1,11 @@
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
@@ -13,10 +14,13 @@
     ]}
     # No additional Altair specific finality tests, yet.
     altair_mods = phase_0_mods
+    # No specific Merge tests yet. TODO: rebase onto Altair testing later.
+    merge_mods = phase_0_mods
 
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: merge_mods,
     }
 
     run_state_test_generators(runner_name="fork_choice", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/operations/main.py b/tests/generators/operations/main.py
index 0c1b84c240..316ccdf10c 100644
--- a/tests/generators/operations/main.py
+++ b/tests/generators/operations/main.py
@@ -1,10 +1,11 @@
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
@@ -23,6 +24,13 @@
         **phase_0_mods,
     }  # also run the previous phase 0 tests
 
+    merge_mods = {
+        **{key: 'eth2spec.test.merge.block_processing.test_process_' + key for key in [
+            'execution_payload',
+        ]},
+        **phase_0_mods,  # TODO: runs phase0 tests. Rebase to include `altair_mods` testing later.
+    }
+
     # TODO Custody Game testgen is disabled for now
     # custody_game_mods = {**{key: 'eth2spec.test.custody_game.block_processing.test_process_' + key for key in [
     #     'attestation',
@@ -35,6 +43,7 @@
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: merge_mods,
     }
 
     run_state_test_generators(runner_name="operations", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/rewards/main.py b/tests/generators/rewards/main.py
index 2a0f14863c..8e50732e18 100644
--- a/tests/generators/rewards/main.py
+++ b/tests/generators/rewards/main.py
@@ -1,10 +1,11 @@
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
@@ -16,9 +17,15 @@
     # No additional altair specific rewards tests, yet.
     altair_mods = phase_0_mods
 
+    # No additional merge specific rewards tests, yet.
+    # Note: Block rewards are non-epoch rewards and are tested as part of block processing tests.
+    # Transaction fees are part of the execution-layer.
+    merge_mods = phase_0_mods
+
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: merge_mods,
     }
 
     run_state_test_generators(runner_name="rewards", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/sanity/main.py b/tests/generators/sanity/main.py
index 7f7fecc676..3bed6672d5 100644
--- a/tests/generators/sanity/main.py
+++ b/tests/generators/sanity/main.py
@@ -1,11 +1,12 @@
 from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.altair import spec as spec_altair
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.merge import spec as spec_merge
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 
 from eth2spec.gen_helpers.gen_from_tests.gen import run_state_test_generators
 
 
-specs = (spec_phase0, spec_altair)
+specs = (spec_phase0, spec_altair, spec_merge)
 
 
 if __name__ == "__main__":
@@ -17,9 +18,15 @@
         'blocks',
     ]}, **phase_0_mods}  # also run the previous phase 0 tests
 
+    # Altair-specific test cases are ignored, but should be included after the Merge is rebased onto Altair work.
+    merge_mods = {**{key: 'eth2spec.test.merge.sanity.test_' + key for key in [
+        'blocks',
+    ]}, **phase_0_mods}  # TODO: Merge inherits phase0 tests for now.
+
     all_mods = {
         PHASE0: phase_0_mods,
         ALTAIR: altair_mods,
+        MERGE: merge_mods,
     }
 
     run_state_test_generators(runner_name="sanity", specs=specs, all_mods=all_mods)
diff --git a/tests/generators/ssz_static/main.py b/tests/generators/ssz_static/main.py
index 94ce023356..1e810f71e2 100644
--- a/tests/generators/ssz_static/main.py
+++ b/tests/generators/ssz_static/main.py
@@ -94,7 +94,7 @@ def cases_fn() -> Iterable[gen_typing.TestCase]:
     settings.append((seed, MAINNET, random_value.RandomizationMode.mode_random, False, 5))
     seed += 1
     # TODO: enable testing for the whole merge spec.
-    for fork in TESTGEN_FORKS + (MERGE,):
+    for fork in TESTGEN_FORKS:
         gen_runner.run_generator("ssz_static", [
             create_provider(fork, config_name, seed, mode, chaos, cases_if_random)
             for (seed, config_name, mode, chaos, cases_if_random) in settings

From ab693c972445a7ba362d2f527447461f377ce82a Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 00:16:22 +0200
Subject: [PATCH 02/17] update spec test constants for merge

---
 tests/core/pyspec/eth2spec/test/helpers/constants.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/helpers/constants.py b/tests/core/pyspec/eth2spec/test/helpers/constants.py
index ccd7b20a20..d8f2a37baf 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/constants.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/constants.py
@@ -7,21 +7,24 @@
 # Some of the Spec module functionality is exposed here to deal with phase-specific changes.
 PHASE0 = SpecForkName('phase0')
 ALTAIR = SpecForkName('altair')
+MERGE = SpecForkName('merge')
 
 # Experimental phases (not included in default "ALL_PHASES"):
-MERGE = SpecForkName('merge')
 SHARDING = SpecForkName('sharding')
 CUSTODY_GAME = SpecForkName('custody_game')
 DAS = SpecForkName('das')
 
 # The forks that pytest runs with.
-ALL_PHASES = (PHASE0, ALTAIR)
+ALL_PHASES = (PHASE0, ALTAIR, MERGE)
 # The forks that output to the test vectors.
-TESTGEN_FORKS = (PHASE0, ALTAIR)
+TESTGEN_FORKS = (PHASE0, ALTAIR, MERGE)
 # TODO: everything runs in parallel to Altair.
 # After features are rebased on the Altair fork, this can be reduced to just PHASE0.
 FORKS_BEFORE_ALTAIR = (PHASE0, MERGE, SHARDING, CUSTODY_GAME, DAS)
 
+# TODO: when rebasing Merge onto Altair, add ALTAIR to this tuple.
+FORKS_BEFORE_MERGE = (PHASE0,)
+
 #
 # Config
 #

From 521cffc3e9c4de950489470eb1eefbf2871a5c33 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 00:17:10 +0200
Subject: [PATCH 03/17] update execution-payload processing to isolate payload
 from block body

---
 specs/merge/beacon-chain.md | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index b9c443962f..d665f1151f 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -146,8 +146,8 @@ def is_transition_completed(state: BeaconState) -> bool:
 #### `is_transition_block`
 
 ```python
-def is_transition_block(state: BeaconState, block_body: BeaconBlockBody) -> bool:
-    return not is_transition_completed(state) and block_body.execution_payload != ExecutionPayload()
+def is_transition_block(state: BeaconState, block: BeaconBlock) -> bool:
+    return not is_transition_completed(state) and block.body.execution_payload != ExecutionPayload()
 ```
 
 #### `compute_time_at_slot`
@@ -168,7 +168,9 @@ def process_block(state: BeaconState, block: BeaconBlock) -> None:
     process_randao(state, block.body)
     process_eth1_data(state, block.body)
     process_operations(state, block.body)
-    process_execution_payload(state, block.body)  # [New in Merge]
+    # Pre-merge, skip execution payload processing
+    if is_transition_completed(state) or is_transition_block(state, block):
+        process_execution_payload(state, block.body.execution_payload)  # [New in Merge]
 ```
 
 #### Execution payload processing
@@ -181,16 +183,10 @@ The body of the function is implementation dependent.
 ##### `process_execution_payload`
 
 ```python
-def process_execution_payload(state: BeaconState, body: BeaconBlockBody) -> None:
+def process_execution_payload(state: BeaconState, execution_payload: ExecutionPayload) -> None:
     """
     Note: This function is designed to be able to be run in parallel with the other `process_block` sub-functions
     """
-    # Pre-merge, skip processing
-    if not is_transition_completed(state) and not is_transition_block(state, body):
-        return
-
-    execution_payload = body.execution_payload
-
     if is_transition_completed(state):
         assert execution_payload.parent_hash == state.latest_execution_payload_header.block_hash
         assert execution_payload.number == state.latest_execution_payload_header.number + 1

From 25d0d673a9b0950c0aa2d0b2406f849c9dca0470 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 00:18:01 +0200
Subject: [PATCH 04/17] start testing of merge functionality

---
 tests/core/pyspec/eth2spec/test/context.py    |   8 +-
 .../pyspec/eth2spec/test/helpers/block.py     |   6 +-
 .../test/helpers/execution_payload.py         |  26 ++++
 .../pyspec/eth2spec/test/merge/__init__.py    |   0
 .../test/merge/block_processing/__init__.py   |   0
 .../test_process_execution_payload.py         | 147 ++++++++++++++++++
 .../eth2spec/test/merge/sanity/__init__.py    |   0
 .../eth2spec/test/merge/sanity/test_blocks.py |  25 +++
 8 files changed, 210 insertions(+), 2 deletions(-)
 create mode 100644 tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
 create mode 100644 tests/core/pyspec/eth2spec/test/merge/__init__.py
 create mode 100644 tests/core/pyspec/eth2spec/test/merge/block_processing/__init__.py
 create mode 100644 tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
 create mode 100644 tests/core/pyspec/eth2spec/test/merge/sanity/__init__.py
 create mode 100644 tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py

diff --git a/tests/core/pyspec/eth2spec/test/context.py b/tests/core/pyspec/eth2spec/test/context.py
index 438e611cf3..8699c65ad3 100644
--- a/tests/core/pyspec/eth2spec/test/context.py
+++ b/tests/core/pyspec/eth2spec/test/context.py
@@ -8,7 +8,7 @@
 from .exceptions import SkippedTest
 from .helpers.constants import (
     PHASE0, ALTAIR,
-    ALL_PHASES, FORKS_BEFORE_ALTAIR,
+    ALL_PHASES, FORKS_BEFORE_ALTAIR, FORKS_BEFORE_MERGE,
 )
 from .helpers.genesis import create_genesis_state
 from .utils import vector_test, with_meta_tags
@@ -365,3 +365,9 @@ def is_post_altair(spec):
     if spec.fork in FORKS_BEFORE_ALTAIR:
         return False
     return True
+
+
+def is_post_merge(spec):
+    if spec.fork in FORKS_BEFORE_MERGE:
+        return False
+    return True
diff --git a/tests/core/pyspec/eth2spec/test/helpers/block.py b/tests/core/pyspec/eth2spec/test/helpers/block.py
index 6949b54bc4..64f4066331 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/block.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/block.py
@@ -1,4 +1,5 @@
-from eth2spec.test.context import is_post_altair
+from eth2spec.test.context import is_post_altair, is_post_merge
+from eth2spec.test.helpers.execution_payload import build_empty_execution_payload
 from eth2spec.test.helpers.keys import privkeys
 from eth2spec.utils import bls
 from eth2spec.utils.bls import only_with_bls
@@ -94,6 +95,9 @@ def build_empty_block(spec, state, slot=None):
     if is_post_altair(spec):
         empty_block.body.sync_aggregate.sync_committee_signature = spec.G2_POINT_AT_INFINITY
 
+    if is_post_merge(spec):
+        empty_block.body.execution_payload = build_empty_execution_payload(spec, state)
+
     apply_randao_reveal(spec, state, empty_block)
     return empty_block
 
diff --git a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
new file mode 100644
index 0000000000..e829e07c76
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
@@ -0,0 +1,26 @@
+
+def build_empty_execution_payload(spec, state):
+    """
+    Assuming a pre-state of the same slot, build a valid ExecutionPayload without any transactions.
+    """
+    latest = state.latest_execution_payload_header
+    timestamp = spec.compute_time_at_slot(state, state.slot)
+    empty_txs = spec.List[spec.OpaqueTransaction, spec.MAX_EXECUTION_TRANSACTIONS]()
+
+    payload = spec.ExecutionPayload(
+        block_hash=spec.Hash32(),
+        parent_hash=latest.block_hash,
+        coinbase=spec.Bytes20(),
+        state_root=latest.state_root,  # no changes to the state
+        number=latest.number + 1,
+        gas_limit=latest.gas_limit,  # retain same limit
+        gas_used=0,  # empty block, 0 gas
+        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,
+    )
+    # 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"))
+
+    return payload
diff --git a/tests/core/pyspec/eth2spec/test/merge/__init__.py b/tests/core/pyspec/eth2spec/test/merge/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/__init__.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
new file mode 100644
index 0000000000..0cf5cef5f2
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
@@ -0,0 +1,147 @@
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+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])
+
+
+def run_execution_payload_processing(spec, state, execution_payload, valid=True, execution_valid=True):
+    """
+    Run ``process_execution_payload``, yielding:
+      - pre-state ('pre')
+      - execution payload ('execution_payload')
+      - execution details, to mock EVM execution ('execution.yml', a dict with 'execution_valid' key and boolean value)
+      - post-state ('post').
+    If ``valid == False``, run expecting ``AssertionError``
+    """
+
+    yield 'pre', state
+    yield 'execution', {'execution_valid': execution_valid}
+    yield 'execution_payload', execution_payload
+
+    if not valid:
+        expect_assertion_error(lambda: spec.process_execution_payload(state, execution_payload))
+        yield 'post', None
+        return
+
+    spec.process_execution_payload(state, execution_payload)
+
+    yield 'post', state
+
+    # TODO: any assertions to make?
+
+
+@with_merge_and_later
+@spec_state_test
+def test_success_first_payload(spec, state):
+    assert not spec.is_transition_completed(state)
+
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_success_regular_payload(spec, state):
+    # TODO: setup state
+    assert spec.is_transition_completed(state)
+
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_success_first_payload_with_gap_slot(spec, state):
+    # TODO: transition gap slot
+
+    assert not spec.is_transition_completed(state)
+
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_success_regular_payload_with_gap_slot(spec, state):
+    # TODO: setup state
+    assert spec.is_transition_completed(state)
+    # TODO: transition gap slot
+
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_execution_first_payload(spec, state):
+    # completely valid payload, but execution itself fails (e.g. block exceeds gas limit)
+
+    # TODO: execution payload.
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False, execution_valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_execution_regular_payload(spec, state):
+    # completely valid payload, but execution itself fails (e.g. block exceeds gas limit)
+
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False, execution_valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_parent_hash_first_payload(spec, state):
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_number_first_payload(spec, state):
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_everything_first_payload(spec, state):
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_timestamp_first_payload(spec, state):
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_timestamp_regular_payload(spec, state):
+    # TODO: execution payload
+    execution_payload = spec.ExecutionPayload()
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
diff --git a/tests/core/pyspec/eth2spec/test/merge/sanity/__init__.py b/tests/core/pyspec/eth2spec/test/merge/sanity/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py
new file mode 100644
index 0000000000..1f9e691671
--- /dev/null
+++ b/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py
@@ -0,0 +1,25 @@
+from eth2spec.test.helpers.state import (
+    state_transition_and_sign_block
+)
+from eth2spec.test.helpers.block import (
+    build_empty_block_for_next_slot
+)
+from eth2spec.test.context import (
+    with_all_phases, spec_state_test
+)
+
+
+@with_all_phases
+@spec_state_test
+def test_empty_block_transition(spec, state):
+    yield 'pre', state
+
+    block = build_empty_block_for_next_slot(spec, state)
+    assert len(block.body.execution_payload.transactions) == 0
+
+    signed_block = state_transition_and_sign_block(spec, state, block)
+
+    yield 'blocks', [signed_block]
+    yield 'post', state
+
+# TODO: tests with EVM, mock or replacement?

From 36032fd115c1be0eef52ac4a68c3cc8672b5ed70 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 00:37:00 +0200
Subject: [PATCH 05/17] update doc about format

---
 tests/formats/operations/README.md | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/tests/formats/operations/README.md b/tests/formats/operations/README.md
index 033c5fdef6..f562a6f2aa 100644
--- a/tests/formats/operations/README.md
+++ b/tests/formats/operations/README.md
@@ -33,17 +33,23 @@ This excludes the other parts of the block-transition.
 
 Operations:
 
-| *`operation-name`*      | *`operation-object`*  | *`input name`*       | *`processing call`*                                             |
-|-------------------------|-----------------------|----------------------|-----------------------------------------------------------------|
-| `attestation`           | `Attestation`         | `attestation`        | `process_attestation(state, attestation)`                       |
-| `attester_slashing`     | `AttesterSlashing`    | `attester_slashing`  | `process_attester_slashing(state, attester_slashing)`           |
-| `block_header`          | `BeaconBlock`         | **`block`**          | `process_block_header(state, block)`                            |
-| `deposit`               | `Deposit`             | `deposit`            | `process_deposit(state, deposit)`                               |
-| `proposer_slashing`     | `ProposerSlashing`    | `proposer_slashing`  | `process_proposer_slashing(state, proposer_slashing)`           |
-| `voluntary_exit`        | `SignedVoluntaryExit` | `voluntary_exit`     | `process_voluntary_exit(state, voluntary_exit)`                 |
-| `sync_aggregate`        | `SyncAggregate`       | `sync_aggregate`     | `process_sync_committee(state, sync_aggregate)` (new in Altair) |
+| *`operation-name`*      | *`operation-object`*  | *`input name`*       | *`processing call`*                                                  |
+|-------------------------|-----------------------|----------------------|----------------------------------------------------------------------|
+| `attestation`           | `Attestation`         | `attestation`        | `process_attestation(state, attestation)`                            |
+| `attester_slashing`     | `AttesterSlashing`    | `attester_slashing`  | `process_attester_slashing(state, attester_slashing)`                |
+| `block_header`          | `BeaconBlock`         | **`block`**          | `process_block_header(state, block)`                                 |
+| `deposit`               | `Deposit`             | `deposit`            | `process_deposit(state, deposit)`                                    |
+| `proposer_slashing`     | `ProposerSlashing`    | `proposer_slashing`  | `process_proposer_slashing(state, proposer_slashing)`                |
+| `voluntary_exit`        | `SignedVoluntaryExit` | `voluntary_exit`     | `process_voluntary_exit(state, voluntary_exit)`                      |
+| `sync_aggregate`        | `SyncAggregate`       | `sync_aggregate`     | `process_sync_committee(state, sync_aggregate)` (new in Altair)      |
+| `execution_payload`     | `ExecutionPayload`    | `execution_payload`  | `process_execution_payload(state, execution_payload)` (new in Merge) |
 
 Note that `block_header` is not strictly an operation (and is a full `Block`), but processed in the same manner, and hence included here.
 
+The `execution_payload` processing normally requires a `verify_execution_state_transition(execution_payload)`,
+a responsibility of an (external) execution engine.
+During testing this execution is mocked, an `execution.yml` is provided instead:
+a dict containing an `execution_valid` boolean field with the verification result.
+
 The resulting state should match the expected `post` state, or if the `post` state is left blank,
  the handler should reject the input operation as invalid.

From 79fc41146d898d80358ff6c746217d827587ee2c Mon Sep 17 00:00:00 2001
From: Mikhail Kalinin <noblesse.knight@gmail.com>
Date: Wed, 5 May 2021 13:37:07 +0600
Subject: [PATCH 06/17] Adjust is_transition_block call in fork-choice

---
 specs/merge/fork-choice.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/specs/merge/fork-choice.md b/specs/merge/fork-choice.md
index 34647f45d1..f478dd7e68 100644
--- a/specs/merge/fork-choice.md
+++ b/specs/merge/fork-choice.md
@@ -75,7 +75,7 @@ def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
     assert get_ancestor(store, block.parent_root, finalized_slot) == store.finalized_checkpoint.root
     
     # [New in Merge]
-    if is_transition_block(pre_state, block.body):
+    if is_transition_block(pre_state, block):
         # Delay consideration of block until PoW block is processed by the PoW node
         pow_block = get_pow_block(block.body.execution_payload.parent_hash)
         assert pow_block.is_processed

From e2be7614cc2224c75ac6c0356dff48a9b31563e0 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 15:35:36 +0200
Subject: [PATCH 07/17] introduce merge fork version

---
 specs/merge/beacon-chain.md | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index d665f1151f..50b9551b0f 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -13,8 +13,8 @@
 - [Introduction](#introduction)
 - [Custom types](#custom-types)
 - [Constants](#constants)
-  - [Transition](#transition)
   - [Execution](#execution)
+- [Configuration](#configuration)
 - [Containers](#containers)
   - [Extended containers](#extended-containers)
     - [`BeaconBlockBody`](#beaconblockbody)
@@ -50,12 +50,6 @@ We define the following Python custom types for type hinting and readability:
 
 ## Constants
 
-### Transition
-
-| Name | Value |
-| - | - |
-| `TRANSITION_TOTAL_DIFFICULTY` | **TBD** |
-
 ### Execution
 
 | Name | Value |
@@ -64,6 +58,16 @@ We define the following Python custom types for type hinting and readability:
 | `MAX_EXECUTION_TRANSACTIONS` | `uint64(2**14)` (= 16,384) |
 | `BYTES_PER_LOGS_BLOOM` | `uint64(2**8)` (= 256) |
 
+## Configuration
+
+Warning: this configuration is not definitive.
+
+| Name | Value |
+| - | - |
+| `MERGE_FORK_VERSION` | `Version('0x02000000')` |
+| `MERGE_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
+| `TRANSITION_TOTAL_DIFFICULTY` | **TBD** |
+
 ## Containers
 
 ### Extended containers

From 470c6dcc6f38093a6991ee8bb78d1385d11d0d08 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 15:35:52 +0200
Subject: [PATCH 08/17] update test runner to handle merge phase

---
 tests/core/pyspec/eth2spec/test/context.py         | 9 +++++++--
 tests/core/pyspec/eth2spec/test/helpers/genesis.py | 3 +++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/context.py b/tests/core/pyspec/eth2spec/test/context.py
index 8699c65ad3..65201c0c43 100644
--- a/tests/core/pyspec/eth2spec/test/context.py
+++ b/tests/core/pyspec/eth2spec/test/context.py
@@ -7,7 +7,7 @@
 
 from .exceptions import SkippedTest
 from .helpers.constants import (
-    PHASE0, ALTAIR,
+    PHASE0, ALTAIR, MERGE,
     ALL_PHASES, FORKS_BEFORE_ALTAIR, FORKS_BEFORE_MERGE,
 )
 from .helpers.genesis import create_genesis_state
@@ -312,7 +312,7 @@ def wrapper(*args, **kw):
                     return None
                 run_phases = [phase]
 
-            if PHASE0 not in run_phases and ALTAIR not in run_phases:
+            if PHASE0 not in run_phases and ALTAIR not in run_phases and MERGE not in run_phases:
                 dump_skipping_message("none of the recognized phases are executable, skipping test.")
                 return None
 
@@ -331,12 +331,17 @@ def wrapper(*args, **kw):
             if ALTAIR in available_phases:
                 phase_dir[ALTAIR] = spec_altair
 
+            if MERGE in available_phases:
+                phase_dir[MERGE] = spec_merge
+
             # return is ignored whenever multiple phases are ran.
             # This return is for test generators to emit python generators (yielding test vector outputs)
             if PHASE0 in run_phases:
                 ret = fn(spec=spec_phase0, phases=phase_dir, *args, **kw)
             if ALTAIR in run_phases:
                 ret = fn(spec=spec_altair, phases=phase_dir, *args, **kw)
+            if MERGE in run_phases:
+                ret = fn(spec=spec_merge, phases=phase_dir, *args, **kw)
 
             # TODO: merge, sharding, custody_game and das are not executable yet.
             #  Tests that specify these features will not run, and get ignored for these specific phases.
diff --git a/tests/core/pyspec/eth2spec/test/helpers/genesis.py b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
index 49af43ec1f..4a34a5eb3f 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/genesis.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/genesis.py
@@ -1,6 +1,7 @@
 from eth2spec.test.helpers.constants import (
     ALTAIR,
     FORKS_BEFORE_ALTAIR,
+    MERGE,
 )
 from eth2spec.test.helpers.keys import pubkeys
 
@@ -28,6 +29,8 @@ def create_genesis_state(spec, validator_balances, activation_threshold):
 
     if spec.fork == ALTAIR:
         current_version = spec.ALTAIR_FORK_VERSION
+    elif spec.fork == MERGE:
+        current_version = spec.MERGE_FORK_VERSION
 
     state = spec.BeaconState(
         genesis_time=0,

From ff3a82e0f38de19559bbba52e2693e01d4dad44f Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 15:40:56 +0200
Subject: [PATCH 09/17] fix transactions field in exec payload helper

---
 tests/core/pyspec/eth2spec/test/helpers/execution_payload.py   | 2 +-
 .../merge/block_processing/test_process_execution_payload.py   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
index e829e07c76..0d035350dc 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
+++ b/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"))
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
index 0cf5cef5f2..f3f521c4b8 100644
--- a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
+++ b/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)
 

From 865d7db5cad448e8d2ac37859a74eff9d8a2d633 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 16:03:52 +0200
Subject: [PATCH 10/17] update altair tests to not collide with Merge + fix
 merge test triggers

---
 .../test_process_sync_committee.py            | 20 +++++++++----------
 .../test_process_sync_committee_updates.py    |  8 ++++----
 .../test/altair/sanity/test_blocks.py         | 17 ++++++++--------
 .../unittests/validator/test_validator.py     |  8 ++++----
 tests/core/pyspec/eth2spec/test/context.py    |  8 ++++++++
 .../pyspec/eth2spec/test/helpers/block.py     |  2 ++
 .../test_process_execution_payload.py         |  5 +----
 .../eth2spec/test/merge/sanity/test_blocks.py |  4 ++--
 8 files changed, 39 insertions(+), 33 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
index e0faf3d0d3..9b415cfbd8 100644
--- a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
+++ b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
@@ -17,7 +17,7 @@
 )
 from eth2spec.test.context import (
     expect_assertion_error,
-    with_all_phases_except,
+    with_altair_and_later,
     with_configs,
     spec_state_test,
     always_bls,
@@ -62,7 +62,7 @@ def get_committee_indices(spec, state, duplicates=False):
         state.randao_mixes[randao_index] = hash(state.randao_mixes[randao_index])
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 def test_invalid_signature_missing_participant(spec, state):
@@ -84,7 +84,7 @@ def test_invalid_signature_missing_participant(spec, state):
     yield from run_sync_committee_processing(spec, state, block, expect_exception=True)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 def test_invalid_signature_extra_participant(spec, state):
@@ -197,7 +197,7 @@ def run_successful_sync_committee_test(spec, state, committee, committee_bits):
     )
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_configs([MINIMAL], reason="to create nonduplicate committee")
 @spec_state_test
 def test_sync_committee_rewards_nonduplicate_committee(spec, state):
@@ -213,7 +213,7 @@ def test_sync_committee_rewards_nonduplicate_committee(spec, state):
     yield from run_successful_sync_committee_test(spec, state, committee, committee_bits)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_configs([MAINNET], reason="to create duplicate committee")
 @spec_state_test
 def test_sync_committee_rewards_duplicate_committee(spec, state):
@@ -229,7 +229,7 @@ def test_sync_committee_rewards_duplicate_committee(spec, state):
     yield from run_successful_sync_committee_test(spec, state, committee, committee_bits)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 def test_sync_committee_rewards_not_full_participants(spec, state):
@@ -240,7 +240,7 @@ def test_sync_committee_rewards_not_full_participants(spec, state):
     yield from run_successful_sync_committee_test(spec, state, committee, committee_bits)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 def test_sync_committee_rewards_empty_participants(spec, state):
@@ -250,7 +250,7 @@ def test_sync_committee_rewards_empty_participants(spec, state):
     yield from run_successful_sync_committee_test(spec, state, committee, committee_bits)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 def test_invalid_signature_past_block(spec, state):
@@ -289,7 +289,7 @@ def test_invalid_signature_past_block(spec, state):
     yield from run_sync_committee_processing(spec, state, invalid_block, expect_exception=True)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_configs([MINIMAL], reason="to produce different committee sets")
 @spec_state_test
 @always_bls
@@ -326,7 +326,7 @@ def test_invalid_signature_previous_committee(spec, state):
     yield from run_sync_committee_processing(spec, state, block, expect_exception=True)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 @with_configs([MINIMAL], reason="too slow")
diff --git a/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py b/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
index 8ffc515072..c914c476d8 100644
--- a/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
+++ b/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
@@ -2,7 +2,7 @@
     always_bls,
     spec_state_test,
     spec_test,
-    with_all_phases_except,
+    with_altair_and_later,
     with_configs,
     with_custom_state,
     single_phase,
@@ -49,7 +49,7 @@ def run_sync_committees_progress_test(spec, state):
     assert state.next_sync_committee == third_sync_committee
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 @with_configs([MINIMAL], reason="too slow")
@@ -60,7 +60,7 @@ def test_sync_committees_progress_genesis(spec, state):
     yield from run_sync_committees_progress_test(spec, state)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 @always_bls
 @with_configs([MINIMAL], reason="too slow")
@@ -73,7 +73,7 @@ def test_sync_committees_progress_not_genesis(spec, state):
     yield from run_sync_committees_progress_test(spec, state)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_custom_state(balances_fn=misc_balances, threshold_fn=lambda spec: spec.EJECTION_BALANCE)
 @spec_test
 @single_phase
diff --git a/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
index 48ab6956b2..ffe7435319 100644
--- a/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/altair/sanity/test_blocks.py
@@ -11,9 +11,8 @@
 from eth2spec.test.helpers.sync_committee import (
     compute_aggregate_sync_committee_signature,
 )
-from eth2spec.test.helpers.constants import PHASE0
 from eth2spec.test.context import (
-    with_all_phases_except,
+    with_altair_and_later,
     spec_state_test,
 )
 
@@ -40,46 +39,46 @@ def run_sync_committee_sanity_test(spec, state, fraction_full=1.0):
     yield 'post', state
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_full_sync_committee_committee(spec, state):
     next_epoch(spec, state)
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=1.0)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_half_sync_committee_committee(spec, state):
     next_epoch(spec, state)
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=0.5)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_empty_sync_committee_committee(spec, state):
     next_epoch(spec, state)
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=0.0)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_full_sync_committee_committee_genesis(spec, state):
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=1.0)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_half_sync_committee_committee_genesis(spec, state):
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=0.5)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_empty_sync_committee_committee_genesis(spec, state):
     yield from run_sync_committee_sanity_test(spec, state, fraction_full=0.0)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @spec_state_test
 def test_inactivity_scores(spec, state):
     for _ in range(spec.MIN_EPOCHS_TO_INACTIVITY_PENALTY + 2):
diff --git a/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py b/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
index 244e1aa7e9..e1f5d38604 100644
--- a/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
+++ b/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
@@ -8,7 +8,7 @@
 from eth2spec.utils.bls import only_with_bls
 from eth2spec.test.context import (
     PHASE0,
-    with_all_phases_except,
+    with_altair_and_later,
     with_state,
 )
 
@@ -25,7 +25,7 @@ def ensure_assignments_in_sync_committee(
         assert spec.is_assigned_to_sync_committee(state, epoch, validator_index)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_state
 def test_is_assigned_to_sync_committee(phases, spec, state):
     epoch = spec.get_current_epoch(state)
@@ -91,7 +91,7 @@ def _get_sync_committee_signature(
 
 
 @only_with_bls()
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_state
 def test_process_sync_committee_contributions(phases, spec, state):
     # skip over slots at genesis
@@ -144,7 +144,7 @@ def _subnet_for_sync_committee_index(spec, i):
     return i // (spec.SYNC_COMMITTEE_SIZE // spec.SYNC_COMMITTEE_SUBNET_COUNT)
 
 
-@with_all_phases_except([PHASE0])
+@with_altair_and_later
 @with_state
 def test_compute_subnets_for_sync_committee(state, spec, phases):
     some_sync_committee_members = list(
diff --git a/tests/core/pyspec/eth2spec/test/context.py b/tests/core/pyspec/eth2spec/test/context.py
index 65201c0c43..775efdcf3c 100644
--- a/tests/core/pyspec/eth2spec/test/context.py
+++ b/tests/core/pyspec/eth2spec/test/context.py
@@ -367,12 +367,20 @@ def wrapper(*args, spec: Spec, **kw):
 
 
 def is_post_altair(spec):
+    if spec.fork == MERGE:  # TODO: remove parallel Altair-Merge condition after rebase.
+        return False
     if spec.fork in FORKS_BEFORE_ALTAIR:
         return False
     return True
 
 
 def is_post_merge(spec):
+    if spec.fork == ALTAIR:  # TODO: remove parallel Altair-Merge condition after rebase.
+        return False
     if spec.fork in FORKS_BEFORE_MERGE:
         return False
     return True
+
+
+with_altair_and_later = with_phases([ALTAIR])  # TODO: include Merge, but not until Merge work is rebased.
+with_merge_and_later = with_phases([MERGE])
diff --git a/tests/core/pyspec/eth2spec/test/helpers/block.py b/tests/core/pyspec/eth2spec/test/helpers/block.py
index 64f4066331..41d0a91316 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/block.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/block.py
@@ -96,6 +96,8 @@ def build_empty_block(spec, state, slot=None):
         empty_block.body.sync_aggregate.sync_committee_signature = spec.G2_POINT_AT_INFINITY
 
     if is_post_merge(spec):
+        if not hasattr(state, 'latest_execution_payload_header'):
+            raise Exception("panic!!!")
         empty_block.body.execution_payload = build_empty_execution_payload(spec, state)
 
     apply_randao_reveal(spec, state, empty_block)
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
index f3f521c4b8..96a657d7a9 100644
--- a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
@@ -1,8 +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])
+from eth2spec.test.context import spec_state_test, expect_assertion_error, always_bls, with_merge_and_later
 
 
 def run_execution_payload_processing(spec, state, execution_payload, valid=True, execution_valid=True):
diff --git a/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py
index 1f9e691671..4a6db41068 100644
--- a/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/merge/sanity/test_blocks.py
@@ -5,11 +5,11 @@
     build_empty_block_for_next_slot
 )
 from eth2spec.test.context import (
-    with_all_phases, spec_state_test
+    with_merge_and_later, spec_state_test
 )
 
 
-@with_all_phases
+@with_merge_and_later
 @spec_state_test
 def test_empty_block_transition(spec, state):
     yield 'pre', state

From cc11328f74d77bf3a914f71c6cbc606620bf0c24 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 16:24:44 +0200
Subject: [PATCH 11/17] fix merge forkchoice tests with mock get_pow_block

---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index 37fbd77950..9e5a546fab 100644
--- a/setup.py
+++ b/setup.py
@@ -441,7 +441,7 @@ def sundry_functions(cls) -> str:
 
 
 def get_pow_block(hash: Bytes32) -> PowBlock:
-    pass
+    return PowBlock(block_hash=hash, is_valid=True, is_processed=True, total_difficulty=TRANSITION_TOTAL_DIFFICULTY)
 
 
 def get_execution_state(execution_state_root: Bytes32) -> ExecutionState:

From 00cd1c3db76c77fe468721075347df683adb8aa3 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 16:31:28 +0200
Subject: [PATCH 12/17] fix forkchoice unittest not recognizing merge spec

---
 .../test/phase0/unittests/fork_choice/test_on_attestation.py  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
index fcc5e2d213..8ff6bbb389 100644
--- a/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
+++ b/tests/core/pyspec/eth2spec/test/phase0/unittests/fork_choice/test_on_attestation.py
@@ -1,7 +1,7 @@
 from eth2spec.test.context import with_all_phases, spec_state_test
 from eth2spec.test.helpers.block import build_empty_block_for_next_slot
 from eth2spec.test.helpers.attestations import get_valid_attestation, sign_attestation
-from eth2spec.test.helpers.constants import PHASE0, ALTAIR
+from eth2spec.test.helpers.constants import PHASE0, ALTAIR, MERGE
 from eth2spec.test.helpers.state import transition_to, state_transition_and_sign_block, next_epoch, next_slot
 from eth2spec.test.helpers.fork_choice import get_genesis_forkchoice_store
 
@@ -19,7 +19,7 @@ def run_on_attestation(spec, state, store, attestation, valid=True):
     spec.on_attestation(store, attestation)
 
     sample_index = indexed_attestation.attesting_indices[0]
-    if spec.fork in (PHASE0, ALTAIR):
+    if spec.fork in (PHASE0, ALTAIR, MERGE):
         latest_message = spec.LatestMessage(
             epoch=attestation.data.target.epoch,
             root=attestation.data.beacon_block_root,

From 2ef6291cbc74237c364c22c4f29f8debafe1d4b0 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 16:41:59 +0200
Subject: [PATCH 13/17] Minimal execution payload test, more merge-specific
 testing in later PR

---
 .../test_process_execution_payload.py         | 109 +-----------------
 1 file changed, 2 insertions(+), 107 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
index 96a657d7a9..acb88b944b 100644
--- a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
@@ -1,6 +1,6 @@
 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_merge_and_later
-
+from eth2spec.test.helpers.state import next_slot
 
 def run_execution_payload_processing(spec, state, execution_payload, valid=True, execution_valid=True):
     """
@@ -31,115 +31,10 @@ def run_execution_payload_processing(spec, state, execution_payload, valid=True,
 @with_merge_and_later
 @spec_state_test
 def test_success_first_payload(spec, state):
+    next_slot(spec, state)
     assert not spec.is_transition_completed(state)
 
-    # TODO: execution payload
     execution_payload = build_empty_execution_payload(spec, state)
 
     yield from run_execution_payload_processing(spec, state, execution_payload)
 
-
-@with_merge_and_later
-@spec_state_test
-def test_success_regular_payload(spec, state):
-    # TODO: setup state
-    assert spec.is_transition_completed(state)
-
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_success_first_payload_with_gap_slot(spec, state):
-    # TODO: transition gap slot
-
-    assert not spec.is_transition_completed(state)
-
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_success_regular_payload_with_gap_slot(spec, state):
-    # TODO: setup state
-    assert spec.is_transition_completed(state)
-    # TODO: transition gap slot
-
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_execution_first_payload(spec, state):
-    # completely valid payload, but execution itself fails (e.g. block exceeds gas limit)
-
-    # TODO: execution payload.
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False, execution_valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_execution_regular_payload(spec, state):
-    # completely valid payload, but execution itself fails (e.g. block exceeds gas limit)
-
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False, execution_valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_parent_hash_first_payload(spec, state):
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_number_first_payload(spec, state):
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_everything_first_payload(spec, state):
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_timestamp_first_payload(spec, state):
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
-
-
-@with_merge_and_later
-@spec_state_test
-def test_bad_timestamp_regular_payload(spec, state):
-    # TODO: execution payload
-    execution_payload = spec.ExecutionPayload()
-
-    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
-

From 56bcb630dbfa487a4797c718e5a0b5c3ac04abc2 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 17:03:29 +0200
Subject: [PATCH 14/17] Lint fixes for merge testing update

---
 .../altair/block_processing/test_process_sync_committee.py   | 1 -
 .../epoch_processing/test_process_sync_committee_updates.py  | 5 +----
 .../test/altair/unittests/validator/test_validator.py        | 1 -
 tests/core/pyspec/eth2spec/test/helpers/execution_payload.py | 2 +-
 .../merge/block_processing/test_process_execution_payload.py | 4 ++--
 5 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
index 9b415cfbd8..db2664b21d 100644
--- a/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
+++ b/tests/core/pyspec/eth2spec/test/altair/block_processing/test_process_sync_committee.py
@@ -9,7 +9,6 @@
     transition_to,
 )
 from eth2spec.test.helpers.constants import (
-    PHASE0,
     MAINNET, MINIMAL,
 )
 from eth2spec.test.helpers.sync_committee import (
diff --git a/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py b/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
index c914c476d8..c909c791c5 100644
--- a/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
+++ b/tests/core/pyspec/eth2spec/test/altair/epoch_processing/test_process_sync_committee_updates.py
@@ -8,10 +8,7 @@
     single_phase,
     misc_balances,
 )
-from eth2spec.test.helpers.constants import (
-    PHASE0,
-    MINIMAL,
-)
+from eth2spec.test.helpers.constants import MINIMAL
 from eth2spec.test.helpers.state import transition_to
 from eth2spec.test.helpers.epoch_processing import (
     run_epoch_processing_with,
diff --git a/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py b/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
index e1f5d38604..c8a894da68 100644
--- a/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
+++ b/tests/core/pyspec/eth2spec/test/altair/unittests/validator/test_validator.py
@@ -7,7 +7,6 @@
 from eth2spec.utils import bls
 from eth2spec.utils.bls import only_with_bls
 from eth2spec.test.context import (
-    PHASE0,
     with_altair_and_later,
     with_state,
 )
diff --git a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
index 0d035350dc..093b7cf2e2 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
@@ -16,7 +16,7 @@ def build_empty_execution_payload(spec, state):
         gas_limit=latest.gas_limit,  # retain same limit
         gas_used=0,  # empty block, 0 gas
         timestamp=timestamp,
-        receipt_root=b"no receipts here" + b"\x00"*16,  # TODO: root of empty MPT may be better.
+        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=empty_txs,
     )
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
index acb88b944b..d45a2689b7 100644
--- a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
@@ -1,7 +1,8 @@
 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_merge_and_later
+from eth2spec.test.context import spec_state_test, expect_assertion_error, with_merge_and_later
 from eth2spec.test.helpers.state import next_slot
 
+
 def run_execution_payload_processing(spec, state, execution_payload, valid=True, execution_valid=True):
     """
     Run ``process_execution_payload``, yielding:
@@ -37,4 +38,3 @@ def test_success_first_payload(spec, state):
     execution_payload = build_empty_execution_payload(spec, state)
 
     yield from run_execution_payload_processing(spec, state, execution_payload)
-

From 8ac59b73170d452c5a8e16f65b8bb14bbe8c5c75 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Wed, 5 May 2021 22:38:16 +0200
Subject: [PATCH 15/17] fix old ssz-static todo comment

---
 tests/generators/ssz_static/main.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/generators/ssz_static/main.py b/tests/generators/ssz_static/main.py
index 1e810f71e2..d86636e85e 100644
--- a/tests/generators/ssz_static/main.py
+++ b/tests/generators/ssz_static/main.py
@@ -93,7 +93,6 @@ def cases_fn() -> Iterable[gen_typing.TestCase]:
     seed += 1
     settings.append((seed, MAINNET, random_value.RandomizationMode.mode_random, False, 5))
     seed += 1
-    # TODO: enable testing for the whole merge spec.
     for fork in TESTGEN_FORKS:
         gen_runner.run_generator("ssz_static", [
             create_provider(fork, config_name, seed, mode, chaos, cases_if_random)

From 76b5974d11692326cbbf513e9c04130aceabeba4 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Thu, 6 May 2021 02:21:52 +0200
Subject: [PATCH 16/17] is_execution_enabled function + misc review fixes

Co-Authored-By: Danny Ryan <dannyjryan@gmail.com>
---
 specs/merge/beacon-chain.md                            | 10 +++++++++-
 tests/core/pyspec/eth2spec/test/context.py             |  1 -
 .../block_processing/test_process_execution_payload.py |  5 ++++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index 50b9551b0f..626a86724c 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -24,6 +24,7 @@
     - [`ExecutionPayloadHeader`](#executionpayloadheader)
 - [Helper functions](#helper-functions)
   - [Misc](#misc)
+    - [`is_execution_enabled`](#is_execution_enabled)
     - [`is_transition_completed`](#is_transition_completed)
     - [`is_transition_block`](#is_transition_block)
     - [`compute_time_at_slot`](#compute_time_at_slot)
@@ -140,6 +141,13 @@ class ExecutionPayloadHeader(Container):
 
 ### Misc
 
+#### `is_execution_enabled`
+
+```python
+def is_execution_enabled(state: BeaconState, block: BeaconBlock) -> bool:
+    return is_transition_completed(state) or is_transition_block(state, block)
+```
+
 #### `is_transition_completed`
 
 ```python
@@ -173,7 +181,7 @@ def process_block(state: BeaconState, block: BeaconBlock) -> None:
     process_eth1_data(state, block.body)
     process_operations(state, block.body)
     # Pre-merge, skip execution payload processing
-    if is_transition_completed(state) or is_transition_block(state, block):
+    if is_execution_enabled(state, block):
         process_execution_payload(state, block.body.execution_payload)  # [New in Merge]
 ```
 
diff --git a/tests/core/pyspec/eth2spec/test/context.py b/tests/core/pyspec/eth2spec/test/context.py
index 775efdcf3c..7a2e61c22d 100644
--- a/tests/core/pyspec/eth2spec/test/context.py
+++ b/tests/core/pyspec/eth2spec/test/context.py
@@ -330,7 +330,6 @@ def wrapper(*args, **kw):
                 phase_dir[PHASE0] = spec_phase0
             if ALTAIR in available_phases:
                 phase_dir[ALTAIR] = spec_altair
-
             if MERGE in available_phases:
                 phase_dir[MERGE] = spec_merge
 
diff --git a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
index d45a2689b7..fb1da87587 100644
--- a/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py
@@ -13,6 +13,8 @@ def run_execution_payload_processing(spec, state, execution_payload, valid=True,
     If ``valid == False``, run expecting ``AssertionError``
     """
 
+    pre_exec_header = state.latest_execution_payload_header.copy()
+
     yield 'pre', state
     yield 'execution', {'execution_valid': execution_valid}
     yield 'execution_payload', execution_payload
@@ -26,7 +28,8 @@ def run_execution_payload_processing(spec, state, execution_payload, valid=True,
 
     yield 'post', state
 
-    # TODO: any assertions to make?
+    assert pre_exec_header != state.latest_execution_payload_header
+    # TODO: any more assertions to make?
 
 
 @with_merge_and_later

From 42733b7e34fa9f0e7fbd9eda0415171e843d0de7 Mon Sep 17 00:00:00 2001
From: protolambda <proto@protolambda.com>
Date: Thu, 6 May 2021 02:27:05 +0200
Subject: [PATCH 17/17] remove merge-test exec-payload trigger debug helper

---
 tests/core/pyspec/eth2spec/test/helpers/block.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tests/core/pyspec/eth2spec/test/helpers/block.py b/tests/core/pyspec/eth2spec/test/helpers/block.py
index 41d0a91316..64f4066331 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/block.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/block.py
@@ -96,8 +96,6 @@ def build_empty_block(spec, state, slot=None):
         empty_block.body.sync_aggregate.sync_committee_signature = spec.G2_POINT_AT_INFINITY
 
     if is_post_merge(spec):
-        if not hasattr(state, 'latest_execution_payload_header'):
-            raise Exception("panic!!!")
         empty_block.body.execution_payload = build_empty_execution_payload(spec, state)
 
     apply_randao_reveal(spec, state, empty_block)