add base hf1 fork function tests

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

@@ -346,13 +346,11 @@ def with_phases(phases, other_phases=None):
             #  A new state-creation helper for phase 1 may be in place, and then phase1+ tests can run without phase0
             available_phases.add(PHASE0)
 
+            # Populate all phases for multi-phase tests
             phase_dir = {}
-            if PHASE0 in available_phases:
-                phase_dir[PHASE0] = spec_phase0
-            if PHASE1 in available_phases:
-                phase_dir[PHASE1] = spec_phase1
-            if LIGHTCLIENT_PATCH in available_phases:
-                phase_dir[LIGHTCLIENT_PATCH] = spec_lightclient_patch
+            phase_dir[PHASE0] = spec_phase0
+            phase_dir[PHASE1] = spec_phase1
+            phase_dir[LIGHTCLIENT_PATCH] = spec_lightclient_patch
 
             # return is ignored whenever multiple phases are ran. If
             if PHASE0 in run_phases:

tests/core/pyspec/eth2spec/test/lightclient_patch/fork/test_fork.py

@@ -0,0 +1,104 @@
+from operator import attrgetter
+
+from eth2spec.test.context import (
+    PHASE0, LIGHTCLIENT_PATCH,
+    spec_state_test, with_phases,
+    with_custom_state,
+    spec_test, with_state,
+    low_balances, misc_balances, large_validator_set,
+)
+from eth2spec.test.helpers.state import (
+    next_slots,
+    next_epoch,
+    next_epoch_via_block,
+    transition_to_slot_via_block,
+)
+
+
+def run_fork_test(spec, pre_state):
+    yield 'pre', pre_state
+
+    post_state = spec.upgrade_to_lightclient_patch(pre_state)
+
+    # Stable fields
+    stable_fields = [
+        'genesis_time', 'genesis_validators_root', 'slot',
+        # History
+        'latest_block_header', 'block_roots', 'state_roots', 'historical_roots',
+        # Eth1
+        'eth1_data', 'eth1_data_votes', 'eth1_deposit_index',
+        # Registry
+        'validators', 'balances',
+        # Randomness
+        'randao_mixes',
+        # Slashings
+        'slashings',
+        # Finality
+        'justification_bits', 'previous_justified_checkpoint', 'current_justified_checkpoint', 'finalized_checkpoint',
+    ]
+    for field in stable_fields:
+        assert getattr(pre_state, field) == getattr(post_state, field)
+
+    # Modified fields
+    modified_fields = ['fork']
+    for field in modified_fields:
+        assert getattr(pre_state, field) != getattr(post_state, field)
+
+    assert pre_state.fork.current_version == post_state.fork.previous_version
+    assert post_state.fork.current_version == spec.LIGHTCLIENT_PATCH_FORK_VERSION
+    assert post_state.fork.epoch == spec.get_current_epoch(post_state)
+
+    yield 'post', post_state
+
+
+@with_phases(([PHASE0]))
+@with_state
+@spec_test
+def test_fork_base_state(spec, phases, state):
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_state
+@spec_test
+def test_fork_next_epoch(spec, phases, state):
+    next_epoch(spec, state)
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_state
+@spec_test
+def test_fork_next_epoch_with_block(spec, phases, state):
+    next_epoch_via_block(spec, state)
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_state
+@spec_test
+def test_fork_many_next_epoch(spec, phases, state):
+    for _ in range(3):
+        next_epoch(spec, state)
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_custom_state(balances_fn=low_balances, threshold_fn=lambda spec: spec.EJECTION_BALANCE)
+@spec_test
+def test_fork_random_low_balances(spec, phases, state):
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_custom_state(balances_fn=misc_balances, threshold_fn=lambda spec: spec.EJECTION_BALANCE)
+@spec_test
+def test_fork_random_misc_balances(spec, phases, state):
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)
+
+
+@with_phases(([PHASE0]))
+@with_custom_state(balances_fn=large_validator_set, threshold_fn=lambda spec: spec.EJECTION_BALANCE)
+@spec_test
+def test_fork_random_large_validator_set(spec, phases, state):
+    yield from run_fork_test(phases[LIGHTCLIENT_PATCH], state)