Move `is_post_xxx` functions to new module

Moving the `is_post_xxx` functions to a separate module allows `genesis`
to also use them (cyclic import from `context` prevented this before).
This allows removing `FORKS_BEFORE_ALTAIR` and `FORKS_BEFORE_BELLATRIX`
constants and adding a more general `is_post_fork` function that needs
less maintenance. This then allows definition of `with_all_phases_from`
to streamline the implementation of the `with_xxx_and_later` decorators.

tests/core/pyspec/eth2spec/test/altair/unittests/test_config_override.py

@@ -1,12 +1,13 @@
 from eth2spec.test.context import (
-    is_post_capella,
-    is_post_eip4844,
     spec_configured_state_test,
     spec_state_test_with_matching_config,
     with_all_phases,
     with_phases,
 )
 from eth2spec.test.helpers.constants import ALTAIR
+from eth2spec.test.helpers.phases import (
+    is_post_capella, is_post_eip4844,
+)
 
 
 @with_phases([ALTAIR])

tests/core/pyspec/eth2spec/test/context.py

@@ -13,9 +13,10 @@ from .exceptions import SkippedTest
 from .helpers.constants import (
     PHASE0, ALTAIR, BELLATRIX, CAPELLA, EIP4844, SHARDING,
     MINIMAL, MAINNET,
-    ALL_PHASES, FORKS_BEFORE_ALTAIR, FORKS_BEFORE_BELLATRIX,
+    ALL_PHASES,
     ALL_FORK_UPGRADES,
 )
+from .helpers.phases import is_post_fork
 from .helpers.typing import SpecForkName, PresetBaseName
 from .helpers.genesis import create_genesis_state
 from .utils import (
@@ -408,6 +409,15 @@ def with_all_phases(fn):
     return with_phases(ALL_PHASES)(fn)
 
 
+def with_all_phases_from(earliest_phase):
+    """
+    A decorator factory for running a tests with every phase except the ones listed
+    """
+    def decorator(fn):
+        return with_phases([phase for phase in ALL_PHASES if is_post_fork(phase, earliest_phase)])(fn)
+    return decorator
+
+
 def with_all_phases_except(exclusion_phases):
     """
     A decorator factory for running a tests with every phase except the ones listed
@@ -417,6 +427,12 @@ def with_all_phases_except(exclusion_phases):
     return decorator
 
 
+with_altair_and_later = with_all_phases_from(ALTAIR)
+with_bellatrix_and_later = with_all_phases_from(BELLATRIX)
+with_capella_and_later = with_all_phases_from(CAPELLA)
+with_eip4844_and_later = with_all_phases_from(EIP4844)
+
+
 def _get_preset_targets(kw):
     preset_name = DEFAULT_TEST_PRESET
     if 'preset' in kw:
@@ -587,28 +603,6 @@ def with_config_overrides(config_overrides):
     return decorator
 
 
-def is_post_altair(spec):
-    return spec.fork not in FORKS_BEFORE_ALTAIR
-
-
-def is_post_bellatrix(spec):
-    return spec.fork not in FORKS_BEFORE_BELLATRIX
-
-
-def is_post_capella(spec):
-    return spec.fork == CAPELLA
-
-
-def is_post_eip4844(spec):
-    return spec.fork == EIP4844
-
-
-with_altair_and_later = with_all_phases_except([PHASE0])
-with_bellatrix_and_later = with_all_phases_except([PHASE0, ALTAIR])
-with_capella_and_later = with_all_phases_except([PHASE0, ALTAIR, BELLATRIX, EIP4844])
-with_eip4844_and_later = with_all_phases_except([PHASE0, ALTAIR, BELLATRIX, CAPELLA])
-
-
 def only_generator(reason):
     def _decorator(inner):
         def _wrapper(*args, **kwargs):

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

@@ -2,10 +2,11 @@ from lru import LRU
 
 from typing import List
 
-from eth2spec.test.context import expect_assertion_error, is_post_altair
+from eth2spec.test.context import expect_assertion_error
 from eth2spec.test.helpers.state import state_transition_and_sign_block, next_epoch, next_slot
 from eth2spec.test.helpers.block import build_empty_block_for_next_slot
 from eth2spec.test.helpers.keys import privkeys
+from eth2spec.test.helpers.phases import is_post_altair
 from eth2spec.utils import bls
 from eth2spec.utils.ssz.ssz_typing import Bitlist
 

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

@@ -1,6 +1,6 @@
-from eth2spec.test.context import is_post_altair, is_post_bellatrix
 from eth2spec.test.helpers.execution_payload import build_empty_execution_payload
 from eth2spec.test.helpers.keys import privkeys
+from eth2spec.test.helpers.phases import is_post_altair, is_post_bellatrix
 from eth2spec.utils import bls
 from eth2spec.utils.bls import only_with_bls
 from eth2spec.utils.ssz.ssz_impl import hash_tree_root

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

@@ -26,9 +26,6 @@ ALL_PHASES = (
 # The forks that output to the test vectors.
 TESTGEN_FORKS = (PHASE0, ALTAIR, BELLATRIX, CAPELLA, EIP4844)
 
-FORKS_BEFORE_ALTAIR = (PHASE0,)
-FORKS_BEFORE_BELLATRIX = (PHASE0, ALTAIR)
-
 # TODO: no EIP4844 fork tests now. Should add when we figure out the content of Capella.
 ALL_FORK_UPGRADES = {
     # pre_fork_name: post_fork_name
@@ -37,7 +34,7 @@ ALL_FORK_UPGRADES = {
     BELLATRIX: CAPELLA,
 }
 ALL_PRE_POST_FORKS = ALL_FORK_UPGRADES.items()
-AFTER_BELLATRIX_UPGRADES = {key: value for key, value in ALL_FORK_UPGRADES.items() if key not in FORKS_BEFORE_ALTAIR}
+AFTER_BELLATRIX_UPGRADES = {key: value for key, value in ALL_FORK_UPGRADES.items() if key != PHASE0}
 AFTER_BELLATRIX_PRE_POST_FORKS = AFTER_BELLATRIX_UPGRADES.items()
 
 #

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

@@ -1,10 +1,8 @@
 from random import Random
 
-from eth2spec.test.context import (
+from eth2spec.test.context import expect_assertion_error
-    is_post_altair,
-    expect_assertion_error,
-)
 from eth2spec.test.helpers.keys import pubkeys, privkeys
+from eth2spec.test.helpers.phases import is_post_altair
 from eth2spec.test.helpers.state import get_balance
 from eth2spec.utils import bls
 from eth2spec.utils.merkle_minimal import calc_merkle_tree_from_leaves, get_merkle_proof

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

@@ -1,5 +1,5 @@
 
-from eth2spec.test.context import is_post_altair
+from eth2spec.test.helpers.phases import is_post_altair
 
 
 def get_process_calls(spec):

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

@@ -1,5 +1,5 @@
 from eth2spec.debug.random_value import get_random_bytes_list
-from eth2spec.test.context import is_post_capella
+from eth2spec.test.helpers.phases import is_post_capella
 
 
 def build_empty_execution_payload(spec, state, randao_mix=None):

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

@@ -1,6 +1,8 @@
 from eth2spec.test.helpers.constants import (
     ALTAIR, BELLATRIX, CAPELLA, EIP4844,
-    FORKS_BEFORE_ALTAIR, FORKS_BEFORE_BELLATRIX,
+)
+from eth2spec.test.helpers.phases import (
+    is_post_altair, is_post_bellatrix,
 )
 from eth2spec.test.helpers.keys import pubkeys
 
@@ -88,7 +90,7 @@ def create_genesis_state(spec, validator_balances, activation_threshold):
         if validator.effective_balance >= activation_threshold:
             validator.activation_eligibility_epoch = spec.GENESIS_EPOCH
             validator.activation_epoch = spec.GENESIS_EPOCH
-        if spec.fork not in FORKS_BEFORE_ALTAIR:
+        if is_post_altair(spec):
             state.previous_epoch_participation.append(spec.ParticipationFlags(0b0000_0000))
             state.current_epoch_participation.append(spec.ParticipationFlags(0b0000_0000))
             state.inactivity_scores.append(spec.uint64(0))
@@ -96,13 +98,13 @@ def create_genesis_state(spec, validator_balances, activation_threshold):
     # Set genesis validators root for domain separation and chain versioning
     state.genesis_validators_root = spec.hash_tree_root(state.validators)
 
-    if spec.fork not in FORKS_BEFORE_ALTAIR:
+    if is_post_altair(spec):
         # Fill in sync committees
         # Note: A duplicate committee is assigned for the current and next committee at genesis
         state.current_sync_committee = spec.get_next_sync_committee(state)
         state.next_sync_committee = spec.get_next_sync_committee(state)
 
-    if spec.fork not in FORKS_BEFORE_BELLATRIX:
+    if is_post_bellatrix(spec):
         # Initialize the execution payload header (with block number and genesis time set to 0)
         state.latest_execution_payload_header = get_sample_genesis_execution_payload_header(
             spec,

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

@@ -0,0 +1,33 @@
+from .constants import (
+    PHASE0, ALTAIR, BELLATRIX, CAPELLA, EIP4844,
+)
+
+
+def is_post_fork(a, b):
+    if a == EIP4844:
+        return b in [PHASE0, ALTAIR, BELLATRIX, EIP4844]
+    if a == CAPELLA:
+        return b in [PHASE0, ALTAIR, BELLATRIX, CAPELLA]
+    if a == BELLATRIX:
+        return b in [PHASE0, ALTAIR, BELLATRIX]
+    if a == ALTAIR:
+        return b in [PHASE0, ALTAIR]
+    if a == PHASE0:
+        return b in [PHASE0]
+    assert False  # Fork is missing
+
+
+def is_post_altair(spec):
+    return is_post_fork(spec.fork, ALTAIR)
+
+
+def is_post_bellatrix(spec):
+    return is_post_fork(spec.fork, BELLATRIX)
+
+
+def is_post_capella(spec):
+    return is_post_fork(spec.fork, CAPELLA)
+
+
+def is_post_eip4844(spec):
+    return is_post_fork(spec.fork, EIP4844)

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

@@ -1,6 +1,6 @@
-from eth2spec.test.context import is_post_altair, is_post_bellatrix
 from eth2spec.test.helpers.block_header import sign_block_header
 from eth2spec.test.helpers.keys import pubkey_to_privkey
+from eth2spec.test.helpers.phases import is_post_altair, is_post_bellatrix
 from eth2spec.test.helpers.state import get_balance
 from eth2spec.test.helpers.sync_committee import (
     compute_committee_indices,

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

@@ -1,8 +1,8 @@
 from random import Random
 
 from eth2spec.test.helpers.attestations import cached_prepare_state_with_attestations
-from eth2spec.test.context import is_post_altair
 from eth2spec.test.helpers.deposits import mock_deposit
+from eth2spec.test.helpers.phases import is_post_altair
 from eth2spec.test.helpers.state import next_epoch
 
 

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

@@ -2,7 +2,7 @@ from random import Random
 from lru import LRU
 
 from eth2spec.phase0.mainnet import VALIDATOR_REGISTRY_LIMIT  # equal everywhere, fine to import
-from eth2spec.test.context import is_post_altair, is_post_bellatrix
+from eth2spec.test.helpers.phases import is_post_altair, is_post_bellatrix
 from eth2spec.test.helpers.state import (
     next_epoch,
 )

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

@@ -1,5 +1,6 @@
-from eth2spec.test.context import expect_assertion_error, is_post_altair
+from eth2spec.test.context import expect_assertion_error
 from eth2spec.test.helpers.block import apply_empty_block, sign_block, transition_unsigned_block
+from eth2spec.test.helpers.phases import is_post_altair
 from eth2spec.test.helpers.voluntary_exits import get_unslashed_exited_validators
 
 

tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_justification_and_finalization.py

@@ -1,8 +1,9 @@
 from random import Random
-from eth2spec.test.context import is_post_altair, spec_state_test, with_all_phases
+from eth2spec.test.context import spec_state_test, with_all_phases
 from eth2spec.test.helpers.epoch_processing import (
     run_epoch_processing_with,
 )
+from eth2spec.test.helpers.phases import is_post_altair
 from eth2spec.test.helpers.state import transition_to, next_epoch_via_block, next_slot
 from eth2spec.test.helpers.voluntary_exits import get_unslashed_exited_validators
 

tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_rewards_and_penalties.py

@@ -5,6 +5,8 @@ from eth2spec.test.context import (
     with_custom_state,
     zero_activation_threshold,
     misc_balances, low_single_balance,
+)
+from eth2spec.test.helpers.phases import (
     is_post_altair,
 )
 from eth2spec.test.helpers.state import (

tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_slashings.py

@@ -1,9 +1,10 @@
 from random import Random
-from eth2spec.test.context import spec_state_test, with_all_phases, is_post_altair, is_post_bellatrix
+from eth2spec.test.context import spec_state_test, with_all_phases
 from eth2spec.test.helpers.epoch_processing import (
     run_epoch_processing_with, run_epoch_processing_to
 )
 from eth2spec.test.helpers.random import randomize_state
+from eth2spec.test.helpers.phases import is_post_altair, is_post_bellatrix
 from eth2spec.test.helpers.state import has_active_balance_differential
 from eth2spec.test.helpers.voluntary_exits import get_unslashed_exited_validators
 from eth2spec.test.helpers.state import next_epoch

tests/core/pyspec/eth2spec/test/phase0/fork_choice/test_get_head.py

@@ -2,7 +2,6 @@ import random
 from eth_utils import encode_hex
 
 from eth2spec.test.context import (
-    is_post_altair,
     spec_state_test,
     with_all_phases,
     with_presets,
@@ -24,6 +23,9 @@ from eth2spec.test.helpers.fork_choice import (
     tick_and_run_on_attestation,
     tick_and_add_block,
 )
+from eth2spec.test.helpers.phases import (
+    is_post_altair,
+)
 from eth2spec.test.helpers.state import (
     next_slots,
     next_epoch,

tests/core/pyspec/eth2spec/test/phase0/genesis/test_initialization.py

@@ -1,5 +1,4 @@
 from eth2spec.test.context import (
-    is_post_altair,
     single_phase,
     spec_test,
     with_presets,
@@ -10,6 +9,9 @@ from eth2spec.test.helpers.deposits import (
     prepare_full_genesis_deposits,
     prepare_random_genesis_deposits,
 )
+from eth2spec.test.helpers.phases import (
+    is_post_altair,
+)
 
 
 def get_post_altair_description(spec):

tests/core/pyspec/eth2spec/test/phase0/genesis/test_validity.py

@@ -1,5 +1,4 @@
 from eth2spec.test.context import (
-    is_post_altair,
     spec_test,
     single_phase,
     with_presets,
@@ -9,6 +8,9 @@ from eth2spec.test.helpers.constants import MINIMAL
 from eth2spec.test.helpers.deposits import (
     prepare_full_genesis_deposits,
 )
+from eth2spec.test.helpers.phases import (
+    is_post_altair,
+)
 
 
 def get_post_altair_description(spec):

tests/core/pyspec/eth2spec/test/phase0/sanity/test_blocks.py

@@ -30,6 +30,7 @@ from eth2spec.test.helpers.sync_committee import (
     compute_sync_committee_participant_reward_and_penalty,
 )
 from eth2spec.test.helpers.constants import PHASE0, MINIMAL
+from eth2spec.test.helpers.phases import is_post_altair, is_post_bellatrix
 from eth2spec.test.context import (
     spec_test, spec_state_test, dump_skipping_message,
     with_phases, with_all_phases, single_phase,
@@ -37,8 +38,6 @@ from eth2spec.test.context import (
     with_presets,
     with_custom_state,
     large_validator_set,
-    is_post_altair,
-    is_post_bellatrix,
 )
 
 

tests/core/pyspec/eth2spec/test/phase0/unittests/test_config_invariants.py

@@ -1,9 +1,11 @@
 from eth2spec.test.context import (
     spec_state_test,
     with_all_phases,
-    is_post_altair, is_post_bellatrix,
 )
 from eth2spec.test.helpers.constants import MAX_UINT_64
+from eth2spec.test.helpers.phases import (
+    is_post_altair, is_post_bellatrix,
+)
 
 
 def check_bound(value, lower_bound, upper_bound):