test(fc): produce block enforces MAX_ATTESTATIONS_DATA limit (#565)

tests/consensus/devnet/fc/test_block_production.py

@@ -1,5 +1,7 @@
 """Fork Choice: Block Production"""
 
+import math
+
 import pytest
 from consensus_testing import (
     AggregatedAttestationCheck,
@@ -14,6 +16,12 @@
     TickStep,
 )
 
+from lean_spec.subspecs.chain.config import (
+    INTERVALS_PER_SLOT,
+    MAX_ATTESTATIONS_DATA,
+    MILLISECONDS_PER_INTERVAL,
+    SECONDS_PER_SLOT,
+)
 from lean_spec.subspecs.containers.slot import Slot
 from lean_spec.subspecs.containers.validator import ValidatorIndex
 
@@ -235,6 +243,94 @@ def test_block_builder_fixed_point_advances_justification(
     )
 
 
+def test_produce_block_enforces_max_attestations_data_limit(
+    fork_choice_test: ForkChoiceTestFiller,
+) -> None:
+    """
+    Block production caps attestation data entries at MAX_ATTESTATIONS_DATA.
+
+    Scenario
+    --------
+    Linear chain through MAX_ATTESTATIONS_DATA + 1 blocks. After building
+    the chain, the same number of aggregated attestations are gossiped —
+    each targeting a different block — producing one more distinct
+    AttestationData entry than the limit allows.
+
+    Timing
+    ------
+    Attestations are gossiped after the aggregate interval of the last
+    chain slot (so the aggregate step is a no-op on an empty pool), then
+    a tick to the next slot start migrates them from "new" to "known".
+
+    Block builder behavior
+    ----------------------
+    The builder sorts entries by target.slot and processes them in order.
+    After selecting MAX_ATTESTATIONS_DATA entries it breaks, excluding the
+    entry with the highest target slot.
+
+    Expected post-state
+    -------------------
+    The produced block contains exactly MAX_ATTESTATIONS_DATA attestations.
+    """
+    limit = int(MAX_ATTESTATIONS_DATA)
+    num_target_blocks = limit + 1
+    block_production_slot = num_target_blocks + 1
+    validators = [ValidatorIndex(0), ValidatorIndex(1), ValidatorIndex(2)]
+
+    # Aggregate fires at interval 2 of the last chain slot.
+    # With an empty pool this is a no-op, so no payloads are lost.
+    # Compute the minimum integer second that reaches this interval.
+    aggregate_interval = num_target_blocks * int(INTERVALS_PER_SLOT) + 2
+    aggregate_time = math.ceil(aggregate_interval * int(MILLISECONDS_PER_INTERVAL) / 1000)
+    # Next slot start migrates gossip payloads from "new" to "known".
+    next_slot_time = block_production_slot * int(SECONDS_PER_SLOT)
+
+    # Build a linear chain. Each block is labeled so attestations can
+    # reference it as a target.
+    chain_steps: list[BlockStep] = [
+        BlockStep(
+            block=BlockSpec(slot=Slot(n), label=f"block_{n}"),
+            checks=(StoreChecks(head_slot=Slot(n)) if n == 1 or n == num_target_blocks else None),
+        )
+        for n in range(1, num_target_blocks + 1)
+    ]
+
+    # One gossip attestation per target block.
+    # Each has a different target checkpoint → num_target_blocks distinct
+    # AttestationData entries.
+    # Source auto-resolves to the genesis justified checkpoint.
+    attestation_steps: list[GossipAggregatedAttestationStep] = [
+        GossipAggregatedAttestationStep(
+            attestation=GossipAggregatedAttestationSpec(
+                validator_ids=validators,
+                slot=Slot(block_production_slot),
+                target_slot=Slot(n),
+                target_root_label=f"block_{n}",
+            ),
+        )
+        for n in range(1, num_target_blocks + 1)
+    ]
+
+    fork_choice_test(
+        steps=[
+            *chain_steps,
+            TickStep(time=aggregate_time),
+            *attestation_steps,
+            TickStep(time=next_slot_time),
+            BlockStep(
+                block=BlockSpec(
+                    slot=Slot(block_production_slot),
+                    label=f"block_{block_production_slot}",
+                ),
+                checks=StoreChecks(
+                    head_slot=Slot(block_production_slot),
+                    block_attestation_count=limit,
+                ),
+            ),
+        ]
+    )
+
+
 def test_produce_block_includes_pending_attestations(
     fork_choice_test: ForkChoiceTestFiller,
 ) -> None:

tests/lean_spec/subspecs/api/test_server.py

@@ -11,8 +11,6 @@
 
 from __future__ import annotations
 
-import asyncio
-
 import httpx
 
 from lean_spec.subspecs.api import ApiServer, ApiServerConfig
@@ -100,8 +98,6 @@ async def test_returns_503_when_store_not_initialized(self) -> None:
 
         finally:
             await server.aclose()
-            server.stop()
-            await asyncio.sleep(0.1)
 
 
 class TestForkChoiceEndpoint:
@@ -121,8 +117,7 @@ async def test_returns_503_when_store_not_initialized(self) -> None:
                 assert response.status_code == 503
 
         finally:
-            server.stop()
-            await asyncio.sleep(0.1)
+            await server.aclose()
 
     async def test_returns_200_with_initialized_store(self, base_store: Store) -> None:
         """Endpoint returns 200 with fork choice tree when store is initialized."""
@@ -169,5 +164,4 @@ async def test_returns_200_with_initialized_store(self, base_store: Store) -> No
                 assert node["weight"] == 0
 
         finally:
-            server.stop()
-            await asyncio.sleep(0.1)
+            await server.aclose()