Adds fork-choice tests

test_libs/pyspec/eth2spec/test/test_fork_choice.py

@@ -0,0 +1,50 @@
+from eth2spec.utils.ssz.ssz_impl import signing_root
+
+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
+from eth2spec.test.helpers.state import next_slot
+
+
+@with_all_phases
+@spec_state_test
+def test_basic(spec, state):
+    # Initialization
+    store = spec.get_genesis_store(state)
+    time = 100
+    spec.on_tick(store, time)
+    assert store.time == time
+
+     # On receiving a block of `GENESIS_SLOT + 1` slot
+    block = build_empty_block_for_next_slot(state)
+    spec.on_block(store, block)
+    assert store.blocks[signing_root(block)] == block
+
+     # On receiving a block of next epoch
+    store.time = time + spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH
+    block = build_empty_block_for_next_slot(state)
+    block.slot += spec.SLOTS_PER_EPOCH
+
+    spec.on_block(store, block)
+    assert store.blocks[signing_root(block)] == block
+
+     # TODO: add tests for justified_root and finalized_root
+
+
+@with_all_phases
+@spec_state_test
+def test_on_attestation(spec, state):
+    store = spec.get_genesis_store(state)
+    time = 100
+    spec.on_tick(store, time)
+
+    next_slot(state)
+
+    attestation = get_valid_attestation(state, slot=1)
+    indexed_attestation = spec.convert_to_indexed(state, attestation)
+    spec.on_attestation(store, attestation)
+    assert (
+        store.latest_targets[indexed_attestation.custody_bit_0_indices[0]] ==
+        spec.Target(attestation.data.target_epoch, attestation.data.target_root)
+    )