Ensure we can send batches where the first message exceeds MAX_PACKET_SIZE (#9068)

tests/integration/test_large_message_batching.py

@@ -0,0 +1,59 @@
+"""Integration test for API handling of large messages exceeding batch size."""
+
+from __future__ import annotations
+
+from aioesphomeapi import SelectInfo
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_large_message_batching(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test API can handle large messages (>1390 bytes) in batches."""
+    # Write, compile and run the ESPHome device, then connect to API
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        # Verify we can get device info
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "large-message-test"
+
+        # List entities - this will include our select with many options
+        entity_info, services = await client.list_entities_services()
+
+        # Find our large select entity
+        large_select = None
+        for entity in entity_info:
+            if isinstance(entity, SelectInfo) and entity.object_id == "large_select":
+                large_select = entity
+                break
+
+        assert large_select is not None, "Could not find large_select entity"
+
+        # Verify the select has all its options
+        # We created 100 options with long names
+        assert len(large_select.options) == 100, (
+            f"Expected 100 options, got {len(large_select.options)}"
+        )
+
+        # Verify all options are present and correct
+        for i in range(100):
+            expected_option = f"Option {i:03d} - This is a very long option name to make the message larger than the typical batch size of 1390 bytes"
+            assert expected_option in large_select.options, (
+                f"Missing option: {expected_option}"
+            )
+
+        # Also verify we can still receive other entities in the same batch
+        # Count total entities - should have at least our select plus some sensors
+        entity_count = len(entity_info)
+        assert entity_count >= 4, f"Expected at least 4 entities, got {entity_count}"
+
+        # Verify we have different entity types (not just selects)
+        entity_types = {type(entity).__name__ for entity in entity_info}
+        assert len(entity_types) >= 2, (
+            f"Expected multiple entity types, got {entity_types}"
+        )