ci(temporal): cache test-server binary to fix temporal.download 429 flakes

.github/workflows/checks.yaml

@@ -93,6 +93,26 @@ jobs:
         uses: ./.github/actions/setup-python-env
         with:
           python-version: ${{ matrix.python-version }}
+      - name: Cache Temporal test server binaries
+        if: runner.os == 'Linux'
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        with:
+          # The temporalio Python SDK downloads its test-server binary into
+          # this directory (filename keyed by SDK version), and reuses any
+          # existing binary on subsequent calls. Caching the directory lets
+          # CI shards share binaries and avoid temporal.download 429s.
+          path: ~/.cache/braintrust/temporal-test-server
+          key: temporal-test-server-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('py/pyproject.toml') }}
+          restore-keys: |
+            temporal-test-server-${{ runner.os }}-${{ runner.arch }}-
+      - name: Configure Temporal test server cache dir
+        if: runner.os == 'Linux'
+        shell: bash
+        run: |
+          set -euo pipefail
+          dir="$HOME/.cache/braintrust/temporal-test-server"
+          mkdir -p "$dir"
+          echo "BRAINTRUST_TEMPORAL_TEST_SERVER_DIR=$dir" >> "$GITHUB_ENV"
       - name: Run nox tests (shard ${{ matrix.shard }}/6)
         shell: bash
         run: |

py/src/braintrust/integrations/temporal/test_temporal.py

@@ -1,6 +1,7 @@
 """Unit tests for Braintrust Temporal interceptor."""
 
 import asyncio
+import os
 import uuid
 from dataclasses import dataclass
 from datetime import timedelta
@@ -243,8 +244,22 @@ def test_contrib_temporal_compat_import_deprecated(self):
 
 @pytest_asyncio.fixture(scope="function")
 async def temporal_env():
-    """Create a Temporal test environment."""
-    async with await temporalio.testing.WorkflowEnvironment.start_time_skipping() as env:
+    """Create a Temporal test environment.
+
+    If ``BRAINTRUST_TEMPORAL_TEST_SERVER_DIR`` is set, point the SDK's binary
+    download cache at that directory and pin a long TTL so existing binaries
+    are reused. CI sets this so a cached directory restored from the GitHub
+    Actions cache shortcuts the download to temporal.download (which rate
+    limits CI runners). When the var is unset (the local default), the SDK
+    falls back to its built-in temp-dir download behavior.
+    """
+    kwargs: dict[str, Any] = {}
+    cache_dir = os.environ.get("BRAINTRUST_TEMPORAL_TEST_SERVER_DIR")
+    if cache_dir:
+        os.makedirs(cache_dir, exist_ok=True)
+        kwargs["download_dest_dir"] = cache_dir
+        kwargs["test_server_download_ttl"] = timedelta(days=365)
+    async with await temporalio.testing.WorkflowEnvironment.start_time_skipping(**kwargs) as env:
         yield env