Spanner Local Tests

Run Spanner Tests Locally

Set up a local Spanner emulator + schema, then run the spanner-backed unit tests. The whole loop is < 90 seconds once the emulator image is cached. This is the fast inner loop for any change touching syncstorage-spanner/.

There are two test surfaces in this repo:

Default to unit tests. Reach for e2e only when changes touch HTTP routing, token handling, or cross-backend behavior CI would catch first.

Quick re-run (after first-time setup)

If the emulator is already up and provisioned:

SYNC_SYNCSTORAGE__SPANNER_EMULATOR_HOST=localhost:9010 \
SYNC_SYNCSTORAGE__DATABASE_URL=spanner://projects/test-project/instances/test-instance/databases/test-database \
RUST_TEST_THREADS=1 \
cargo test --no-default-features --features=syncstorage-db/spanner --package syncstorage-db

If the emulator is not running, use the helper:

./scripts/spanner-local-test-setup.sh

That script brings up the emulator, provisions the database/schema, and runs the suite. It's idempotent — re-running just executes the tests if the stack is already up.

From scratch — the full flow

1. Prerequisites

• Docker Desktop running. The emulator runs as a container.
• Rust toolchain matching rust-toolchain.toml (or close).
• For e2e only: enough Docker memory (≥ 8 GB recommended) — the app:build image compiles grpcio-sys from source and OOMs on small allocations.

2. Start the emulator

docker compose -f docker/docker-compose.spanner.yaml up -d sync-db

This starts the gcr.io/cloud-spanner-emulator/emulator image. Two ports:

• 9010 — gRPC. The Rust client (and production) talk this.
• 9020 — REST. Used for admin (create instance / create database / DDL).

Wait ~2 seconds for the emulator to be ready. Confirm:

curl -fsS -o /dev/null http://localhost:9020/v1/projects/test-project/instances && echo ok

3. Create the instance and database

curl -fsS -X POST "http://localhost:9020/v1/projects/test-project/instances" \
  -H 'Content-Type: application/json' \
  -d '{"instance":{"config":"emulator-test-config","nodeCount":1,"displayName":"Test"},"instanceId":"test-instance"}'

curl -fsS -X POST "http://localhost:9020/v1/projects/test-project/instances/test-instance/databases" \
  -H 'Content-Type: application/json' \
  -d '{"createStatement":"CREATE DATABASE `test-database`"}'

4. Apply the schema

⚠️ Do not run scripts/prepare-spanner.sh directly on macOS. Its sed invocation uses GNU \+ syntax that BSD sed doesn't accept. The script is designed to run inside the Linux container (where GNU sed lives). When you run it from a macOS host, the DDL parsing silently returns an empty array, the database gets created with no tables, and tests fail with cryptic "Table not found: collections" errors.

Use this macOS-safe inline equivalent:

DDL_STATEMENTS=$(grep -v '^--' syncstorage-spanner/src/schema.ddl \
  | tr '\n' ' ' \
  | tr -s ' ' \
  | sed 's/;[[:space:]]*$//' \
  | jq -R -s -c 'split(";") | map(select(length > 0)) | map(gsub("^\\s+|\\s+$";""))')

PAYLOAD=$(jq -n --argjson stmts "$DDL_STATEMENTS" '{statements:$stmts}')

curl -fsS -X PATCH "http://localhost:9020/v1/projects/test-project/instances/test-instance/databases/test-database/ddl" \
  -H 'Content-Type: application/json' \
  -d "$PAYLOAD"

Then verify the tables landed:

curl -fsS "http://localhost:9020/v1/projects/test-project/instances/test-instance/databases/test-database/ddl" \
  | jq '.statements | length'
# expected: 8 (5 tables + 3 indexes + 2 row-deletion policies, the last 2 are folded into CREATE TABLE statements by the emulator)

5. Run the unit tests

SYNC_SYNCSTORAGE__SPANNER_EMULATOR_HOST=localhost:9010 \
SYNC_SYNCSTORAGE__DATABASE_URL=spanner://projects/test-project/instances/test-instance/databases/test-database \
RUST_TEST_THREADS=1 \
cargo test --no-default-features --features=syncstorage-db/spanner --package syncstorage-db

Two non-obvious env vars:

• SYNC_SYNCSTORAGE__SPANNER_EMULATOR_HOST — the gRPC endpoint. This is what tells the client to skip OAuth. If you leave it unset, every test fails with "Error occurred when fetching oauth2 token" because the client tries to authenticate against the real Google API.
• RUST_TEST_THREADS=1 — required. Many tests share the same database and assert on counts/timestamps; parallel runs race.

Expected output: test result: ok. 39 passed; 0 failed; ….

6. Run a single test

SYNC_SYNCSTORAGE__SPANNER_EMULATOR_HOST=localhost:9010 \
SYNC_SYNCSTORAGE__DATABASE_URL=spanner://projects/test-project/instances/test-instance/databases/test-database \
RUST_TEST_THREADS=1 \
cargo test --no-default-features --features=syncstorage-db/spanner --package syncstorage-db \
  tests::db::delete_collection_tombstone -- --nocapture

--nocapture is essential when tests fail — without it, errors get swallowed.

7. Teardown

docker compose -f docker/docker-compose.spanner.yaml down -v

The -v wipes named volumes for the whole compose project — including tokenserver_db_data. If you have the full e2e stack (or anything else from this compose file) running in parallel, prefer the helper script's narrower teardown instead:

./scripts/spanner-local-test-setup.sh down

That only stops + removes the sync-db container. The emulator keeps no data in named volumes, so next run starts from a fresh database either way.

Common failures

Docker e2e (optional, slower path)

The Makefile target docker_run_spanner_e2e_tests spins up the full stack and runs the Python integration suite twice (with and without JWK cache). It requires the app:build image to be current — built against the working tree's code.

docker build -t app:build .
mkdir -p workflow/test-results
SYNCSTORAGE_RS_IMAGE=app:build make docker_run_spanner_e2e_tests

Two local-run-only gotchas the make target assumes CI handles:

• SYNCSTORAGE_RS_IMAGE=app:build must be exported. docker-compose.spanner.yaml:52 references ${SYNCSTORAGE_RS_IMAGE:-syncstorage-rs:latest}; without the override compose tries to pull a non-existent syncstorage-rs:latest from Docker Hub. CI sets it in .github/workflows/main-workflow.yml. Local doesn't get it for free.
• workflow/test-results/ must exist before the make target runs. The target uses docker cp ... ${INT_SPANNER_NO_JWK_JUNIT_XML} which writes into that directory; if missing, the docker cp fails with invalid output path and aborts the run.

Two tests will always fail locally and can be safely ignored:

• tools/integration_tests/tokenserver/test_e2e.py::test_unauthorized_oauth_error_status
• tools/integration_tests/tokenserver/test_e2e.py::test_valid_oauth_request

Both hit real FxA stage (api-accounts.stage.mozaws.net, oauth.stage.mozaws.net) and need live network + production credentials the docker stack doesn't have. They surface as fxa.errors.OutOfProtocolError: API responded with non-json content-type — FxA returning an HTML error page because the request can't authenticate. CLAUDE.md excludes these from make run_local_e2e_tests via --ignore=tokenserver/test_e2e.py; the docker e2e target doesn't apply that exclusion, so expect 149 passed, 2 errors not 151 passed.

Notes:

• The image build compiles grpcio-sys from C++ source. On Docker Desktop for Mac, allocate ≥ 8 GB memory.
• The build takes 10-20 minutes from cold. Subsequent rebuilds reuse cache layers and are much faster unless Cargo.lock or the Rust toolchain changed.
• Results land in workspace/test-results/ as JUnit XML.
• The make target tears the stack down on completion.

ar: unable to copy file 'libgrpc.a'; reason: Success

Misleading message — the linker wasn't killed, the BuildKit cache mount got into a corrupt state. Seen on macOS with stale buildkit caches (mine had ~19 GB accumulated).

Fix:

⚠️ docker builder prune -f clears BuildKit cache mounts for every Docker project on the host, not just this repo. Unrelated projects' next builds will go from cached to cold. Run it only when the link error reproduces and you've ruled out a real OOM.

docker builder prune -f
docker build -t app:build .

The prune drops the cache mounts grpcio-sys writes its 100+ MB libgrpc.a into. The next build re-creates them clean and the link step succeeds. If it fails a second time after prune, then suspect a real OOM and bump Docker Desktop memory.

If the local build won't cooperate, CI on push runs the same e2e suite — relying on it is reasonable for refactors that don't touch HTTP/auth/routing.

When to invoke this skill

Reach for it when:

• You're editing anything under syncstorage-spanner/ and want to validate before pushing.
• A spanner test is failing in CI and you need to reproduce locally.
• You're investigating an emulator-vs-prod behavior question.
• You forgot the env-var dance for the third time this month.

Don't invoke it for changes that don't touch Spanner — the MySQL or Postgres backends have their own test paths through the Makefile's test_with_coverage and postgres_test_with_coverage targets.

Output format

After running, report:

1. Emulator state: running / fresh / pre-existing
2. Schema applied: N statements
3. Test results: X passed; Y failed; Z ignored — list the failed test names if any
4. Total wall time
5. Teardown: done / left running for follow-up

If anything failed, surface the actual error message (not just the test name) — Spanner emulator errors are verbose but informative, and the first line is usually enough to diagnose.