Testing Materialize

Unit tests

Run unit tests with cargo test. If available, use cargo nextest instead. If these complain about METADATA_BACKEND_URL, then use bin/cargo-test instead. When using -p, our packages typically have an mz- suffix, e.g., mz-adapter. Rewrite datadriven test expectations with REWRITE=1 cargo test .... Do not manually update *.snap files. Use cargo test followed by cargo insta accept to update snapshot files.

Some tests require access to a metadata store. Set environment variables to COCKROACH_URL=postgres://root@localhost:26257 METADATA_BACKEND_URL=postgres://root@localhost:26257.

Control log output during tests with MZ_TEST_LOG_FILTER=<level>, e.g. MZ_TEST_LOG_FILTER=debug cargo test ....

The first run includes a cargo build step that can take several minutes. Use a bash timeout of at least 600000ms (10 min) for test commands.

sqllogictest

Run sqllogictest files with:

bin/sqllogictest --optimized -- PATH

PATH is relative to the repo root, usually a file in test/sqllogictest/. Rewrite expected results with bin/sqllogictest -- --rewrite-results PATH. For large test files, --optimized significantly improves execution speed at the cost of longer compile time. You can use -v for printing each query before it is run, e.g. to figure out where we are crashing.

Testdrive

Run testdrive files with:

bin/mzcompose --find testdrive run default -- FILENAME.td

FILENAME.td is a file in test/testdrive/, relative to that directory (not the repo root).

Some compositions (e.g. platform-checks, upgrade, pg-cdc multi-version) run the same .td file against multiple Materialize versions. When a change alters version-sensitive output (e.g. the result of a SHOW, a system-catalog query, or the exact text of an error message), gate the affected lines with version guards so each version asserts on the output it actually produces:

>[version<2602300] SHOW some_setting
old_default

>[version>=2602300] SHOW some_setting
new_default

![version<2602300] SELECT * FROM t1_update;
contains:Invalid data in source, saw retractions

![version>=2602300] SELECT * FROM t1_update;
contains:negative record multiplicity

The [version...] guard goes immediately after the directive sigil (> for a query expecting success, ! for one expecting an error, etc.) and before the SQL. The version is encoded as MMmmmpp (e.g. 26.23.0 → 2602300); see src/build-info/src/lib.rs::version_num. Existing examples: test/pg-cdc-old-syntax/privileges.td, test/pg-cdc/publication-with-publish-option.td.

pgtest

Run pgtest files with:

bin/cargo-test -p mz-environmentd pgtest

Run a specific pgtest file: bin/cargo-test -p mz-environmentd test_pgtest_FILE_NAME.

mzcompose

NAME is any directory containing an mzcompose.py file.

Run mzcompose compositions with:

bin/mzcompose --find NAME run WORKFLOW

default is a valid workflow in many compositions, provided a workflow_default exists that iterates over all workflows. Not all compositions have a workflow_default.

Other useful commands:

• bin/mzcompose --find NAME list — list available compositions
• bin/mzcompose --find NAME list-workflows — list workflows for a composition
• bin/mzcompose --find NAME logs — view container logs
• bin/mzcompose --find NAME down — stop a composition

Many tests expect to start with fresh state. Run bin/mzcompose --find NAME down between test runs, not just at the end of a session.

mzcompose builds optimized binaries by default, which are nearly as fast to run as release and much faster to link than debug builds.

• --release builds full release binaries, which can be slow. Instead of building release locally, let CI build the binary by creating a (draft) pull request and waiting for the build jobs to finish. Afterward, mzcompose will attempt to download the binaries instead of building them locally.
• --dev builds non-optimized debug binaries locally.

Reproducing bugs

Reproducing bugs is a manual process. Ask the user for reproduction instructions, or point them to the GitHub issue or the Buildkite annotation under "Test details & reproducer".

Many tests expect fresh state. Always run bin/mzcompose --find NAME down before attempting to reproduce.

For flaky tests, the user can run in a loop until failure:

while true; do
    bin/mzcompose --find testdrive down && \
    bin/mzcompose --find testdrive run default FILENAME.td || break
done

If a flake cannot be reproduced locally, suggest the user trigger CI runs manually via https://ci.dev.materialize.com/trigger Removing the "Target Branch" generates a random identifier, allowing parallel runs. 10-20 runs to reproduce a flake is fine.

Additional logging for flaky tests

Add logging through log_filter in the test's mzcompose.py:

Materialized(
    additional_system_parameter_defaults={
        # TODO: Remove when database-issues#NNNN is fixed
        "log_filter": "mz_storage::source::postgres=trace"
    },
)

If the flake might occur anywhere, extend get_minimal_system_parameters in misc/python/materialize/mzcompose/__init__.py with a log_filter. Always add a TODO comment referencing the issue.

Adding a test

Determine the right framework based on what you're testing:

• SQL correctness, types, functions (no external systems, no concurrency): sqllogictest (.slt in test/sqllogictest/). Use mode cockroach, test NULLs and edge cases. Do NOT modify files in test/sqllogictest/sqlite or test/sqllogictest/cockroach (upstream). When adding new tests to slt files, prefer adding them to an existing slt file rather than creating new slt files, if you are able to quickly find an existing slt file where the new tests fit naturally.
• Sources/sinks, Kafka, catalog, pgwire (external systems): testdrive (.td in test/testdrive/). Frameworks like pg-cdc, mysql-cdc, sql-server-cdc, kafka-* have targeted setups but also run testdrive files.
• Raw pgwire messages (COPY, extended protocol): pgtest (.pt in test/pgtest/). Wire new files in src/environmentd/tests/pgwire.rs.
• Pure logic, decoding, pure functions: Rust #[mz_ore::test] (or #[mz_ore::test(tokio::test)] for async).
• Restart/upgrade issues: Platform Checks. See doc/developer/platform-checks.md, especially the "Writing a Check" section. Do not use the old Legacy Upgrade tests.
• Panics or unexpected query errors under concurrency: extend Parallel Workload actions in misc/python/materialize/parallel_workload/action.py.
• Many objects / limits: add a Generator subclass in test/limits/mzcompose.py.
• OOM / bounded memory: add a Scenario in test/bounded-memory/mzcompose.py.
• Performance micro-benchmarks: Feature Benchmark scenarios in misc/python/materialize/feature_benchmark/scenarios. See doc/developer/feature-benchmark.md.

In most cases, appending to an existing .slt or .td file is sufficient. For functional issues, aim for at least two different test frameworks that can independently detect the regression.

Read doc/developer/guide-testing.md for more detail on test frameworks.