fix: resolve StopIteration error in BigQuery emulator fixture (#99)

Fixed a `RuntimeError: generator raised StopIteration` that prevented the BigQuery emulator fixture from starting Docker containers. This issue affected BigQuery tests and could potentially impact other database services under certain conditions.

Author: cofin

.pre-commit-config.yaml

@@ -2,7 +2,7 @@ exclude: "^docs/conf.py"
 
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
+    rev: v6.0.0
     hooks:
       - id: trailing-whitespace
       - id: check-added-large-files
@@ -19,7 +19,7 @@ repos:
 
   # Ruff replaces black, flake8, autoflake and isort
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: "v0.11.11" # make sure this is always consistent with hatch configs
+    rev: "v0.13.3" # make sure this is always consistent with hatch configs
     hooks:
       - id: ruff
         args: [--config, ./pyproject.toml]

src/pytest_databases/_service.py

@@ -10,10 +10,10 @@
 
 import filelock
 import pytest
-from docker import DockerClient
 from docker.errors import APIError, ImageNotFound
 from typing_extensions import Self
 
+from docker import DockerClient
 from pytest_databases.helpers import get_xdist_worker_id
 from pytest_databases.types import ServiceContainer
 
@@ -139,6 +139,7 @@ def run(
         shm_size: int | None = None,
         mem_limit: str | None = None,
         platform: str | None = None,
+        protocol: str = "tcp",
     ) -> Generator[ServiceContainer, None, None]:
         if check is None and wait_for_log is None:
             msg = "Must set at least check or wait_for_log"
@@ -176,17 +177,32 @@ def run(
                 # spins it up and the metadata becomes available, so we're redoing the
                 # check with a small incremental backup here
                 for i in range(10):
+                    container.reload()
                     if any(v for v in container.ports.values()):
                         break
-                    container.reload()
                     time.sleep(0.1 + (i / 10))
                 else:
                     msg = f"Service {name!r} failed to create container"
                     raise ValueError(msg)
 
-        host_port = int(
-            container.ports[next(k for k in container.ports if k.startswith(str(container_port)))][0]["HostPort"]
-        )
+        # Get port binding based on protocol configuration
+        binding = None
+        if protocol == "both":
+            binding = container.ports.get(f"{container_port}/tcp") or container.ports.get(f"{container_port}/udp")
+        elif protocol in {"tcp", "udp"}:
+            binding = container.ports.get(f"{container_port}/{protocol}")
+        else:
+            msg = f"Invalid protocol '{protocol}'. Must be 'tcp', 'udp', or 'both'."
+            raise ValueError(msg)
+
+        if not binding:
+            msg = (
+                f"Container port {container_port}/{protocol} not found in exposed ports. "
+                f"Available ports: {list(container.ports.keys())}"
+            )
+            raise RuntimeError(msg)
+
+        host_port = int(binding[0]["HostPort"])
         service = ServiceContainer(
             host=container_host,
             port=host_port,

tests/test_redis.py

@@ -95,8 +95,8 @@ def test_two({redis_compatible_service}: RedisService) -> None:
     assert not client.get("one")
     client.set("one", "1")
     assert client.get("one") == b"1"
-    
-    
+
+
 def test_use_same_db({redis_compatible_service}: RedisService) -> None:
     client_0 = redis.Redis(host={redis_compatible_service}.host, port={redis_compatible_service}.port, db=0)
     client_1 = redis.Redis(host={redis_compatible_service}.host, port={redis_compatible_service}.port, db=1)