Test Framework

The tenzir-test harness discovers and runs integration tests for pipelines, fixtures, and custom runners. Use this page as a reference for concepts, configuration, and CLI details. For step-by-step walkthroughs, see the guides for running tests, writing tests, creating fixtures, and adding custom runners.

Install

tenzir-test ships as a Python package that requires Python 3.12 or later. Install it with uv (or pip) and verify the console script:

uv add tenzir-test
uvx tenzir-test --help

Core concepts

• Project root – Directory passed to --root; typically contains fixtures/, inputs/, runners/, and tests/.
• Mode – Auto-detected as project or package. A package.yaml in the current directory (or its parent when you run from <package>/tests) switches to package mode.
• Library – A root that contains multiple packages (each with a package.yaml and its own tests/). The harness can discover all packages under such a library root and run their suites in one invocation. Use --package-dirs to load packages so their operators can cross-import.
• Test – Any supported file under tests/; frontmatter controls execution.
• Runner – Named strategy that executes a test (tenzir, python, custom entries).
• Fixture – Reusable environment provider registered under fixtures/ and requested via frontmatter.
• Suite – Directory-owned group of tests that share fixtures. Declare it with suite: in a test.yaml; all descendants join automatically. Members run sequentially by default, or concurrently when mode: parallel is set.
• Input – Data accessed with TENZIR_INPUTS; defaults to <root>/inputs but you can override it per directory or per test with an inputs: setting. The harness also supports inline inputs via TENZIR_INPUT for test-specific data files.
• Stdin – Content piped to the test process via a .stdin file placed next to the test. The harness exposes the file path via TENZIR_STDIN and automatically pipes its content to the subprocess stdin.
• Scratch directory – Ephemeral workspace exposed as TENZIR_TMP_DIR during each test run.
• Artifact / Baseline – Runner output persisted next to the test; regenerate with --update.
• Configuration sources – Frontmatter plus inherited test.yaml files; tenzir.yaml still configures the Tenzir binary.

A typical project layout looks like this:

project-root/
├── fixtures/
│   └── __init__.py
├── inputs/
│   └── sample.ndjson
├── runners/
│   └── __init__.py
└── tests/
    ├── alerts/
    │   ├── sample.tql
    │   └── sample.txt
    ├── parsing/
    │   ├── csv.input           # Inline input for this test
    │   ├── csv.tql
    │   └── csv.txt
    ├── shell/
    │   ├── echo.sh
    │   ├── echo.stdin          # Stdin content piped to the test
    │   └── echo.txt
    └── python/
        └── quick-check.py

For a package layout (with package.yaml), the structure may look like:

my-package/
├── package.yaml
├── operators/
│   └── custom-op.tql
├── pipelines/
│   └── smoke.tql
└── tests/
    ├── inputs/
    │   └── sample.ndjson
    ├── fixtures/
    │   └── __init__.py
    ├── runners/
    │   └── __init__.py
    └── pipelines/
        ├── custom-op.tql
        └── custom-op.txt

Execution modes and packages

• Mode resolution:
  • --root with tests/ → project mode.
  • --root (or its parent when named tests) with a package.yaml → package mode.
• In package mode the harness exposes:
  • TENZIR_PACKAGE_ROOT – Absolute package directory.
  • TENZIR_INPUTS – <package>/tests/inputs/ unless a directory test.yaml or the test frontmatter overrides it.
  • --package-dirs=<package> – Passed automatically to the tenzir binary.
• Without a manifest the harness stays in project mode, recursively discovers tests under tests/, and applies global fixtures, runners, and inputs.

CLI reference

Run the tests from the project root:

uvx tenzir-test

Useful options:

• --update: Rewrite reference artifacts next to each test.
• --purge: Remove generated artifacts (diffs, text outputs) from previous runs.
• --jobs N: Control concurrency (4 * CPU cores by default).
• --coverage and --coverage-source-dir: Enable LLVM coverage.
• -k, --keep: Preserve per-test scratch directories instead of deleting them (same as setting TENZIR_KEEP_TMP_DIRS=1).
• --package-dirs <path>: Extra package directories for Tenzir binaries. Repeatable and accepts comma-separated lists. Entries merge with any package-dirs: declared in directory test.yaml files, then get normalized, de-duplicated, and exported via TENZIR_PACKAGE_DIRS.
• --debug: Emit framework-level diagnostics (fixture lifecycle, discovery notes, comparison targets, etc.) and automatically enable verbose output so you see all test results (pass/skip/fail) instead of only failures. The same mode is available via TENZIR_TEST_DEBUG=1.
• --summary: Print the tabular breakdown and failure tree after each project.
• --diff/--no-diff: Toggle unified diff output for failed comparisons. Diffs are shown by default; disable them when you only need aggregated statistics.
• --diff-stat/--no-diff-stat: Show (or suppress) the per-file change counter, which summarises additions and deletions even when the diff body is hidden.
• -p, --passthrough: Stream raw stdout/stderr to the terminal instead of comparing against reference artifacts. The harness forces single-job execution (overriding --jobs when necessary) and ignores --update while passthrough is active. Passthrough mode automatically enables verbose output.
• -v, --verbose: Print individual test results as they complete. By default (quiet mode) the harness only shows failures and a compact summary, significantly reducing noise for large test suites. Verbose mode displays passing and skipped tests alongside failures. Use --summary together with --verbose to include the tree summary at the end of the run.
• --run-skipped: Run all skipped tests unconditionally. Both static skips (skip: reason) and conditional skips (skip: {on: fixture-unavailable}) are bypassed. When a fixture raises FixtureUnavailable and --run-skipped is active, the exception propagates as a hard failure instead of being caught. This is the sledgehammer approach---use it when you want to force every skipped test to execute regardless of its skip reason.
• --run-skipped-reason: Selectively run skipped tests whose reason matches a substring or glob pattern. Bare strings match as substrings; patterns containing *, ?, or [ use fnmatch syntax---the same matching semantics as --match. Repeatable; a test runs if its skip reason matches any provided pattern. The match applies to the final displayed reason, including the fixture unavailable: prefix for conditional skips. When both --run-skipped and --run-skipped-reason are provided, --run-skipped takes precedence and all skipped tests run. When no skipped tests match the reason filters, the harness prints a diagnostic message.
• -a, --all-projects: Run the root project together with any satellites provided on the command line.
• -m, --match: Select tests whose relative path matches a substring or glob pattern. Bare strings (without *, ?, or [) match as substrings, so -m mysql selects any test with “mysql” anywhere in its path. Patterns containing glob metacharacters use fnmatch syntax. Repeatable; tests matching any pattern are selected. When combined with positional TEST paths, only tests matching both are run (intersection).
• --fixture: Activate fixtures in standalone foreground mode without running tests. Repeatable. Accepts bare names (--fixture mysql) or YAML mapping specs (--fixture 'kafka: {port: 9092}'). When provided, positional TEST arguments are not allowed. See the run fixtures guide.

Set TENZIR_TEST_DEBUG=1 in CI when you want the same diagnostics without passing --debug on the command line.

Python API

The harness is also available as a typed Python library. Import tenzir_test and call execute() when you need to run scenarios from automation or another tool without shelling out to the CLI:

from pathlib import Path

from tenzir_test import ExecutionResult, execute

result: ExecutionResult = execute(tests=[Path("tests/pipeline.tql")])
if result.exit_code:
    # propagate non-zero status to your orchestration layer
    raise SystemExit(result.exit_code)
for project in result.project_results:
    print(project.selection.root, project.summary.total)

The helper mirrors the CLI options but returns an ExecutionResult with aggregated Summary objects and metadata you can inspect or serialize. Errors surface as HarnessError exceptions so callers can control reporting and retry logic.

Selections

A selection is the ordered list of positional paths you pass after the CLI flags. Each element can point to a single test file, a directory, or an entire project. The harness resolves every element relative to the current working directory first and then relative to the root project. How you shape the selection determines which projects run:

• No positional arguments → run every test in the root project.
• Paths inside the root project → run only those targets (plus any explicitly named satellites).
• Paths that resolve to satellite projects → run those satellites, skipping the root unless you also request it.

Use --all-projects when you want the root project to execute alongside a selection that only names satellites. This keeps the CLI predictable: the selection lists the exact satellites you care about, and the flag opts the root back in without duplicating its path on the command line.

Suites

Suites let you run several tests under one shared fixture lifecycle. Declare a suite in a directory-level test.yaml; the definition applies to every test under that directory, including nested subdirectories.

The suite key accepts a plain string or a mapping with name and mode:

# tests/http/test.yaml — sequential (default)
suite: smoke-http
fixtures: [http]
timeout: 45

The mapping form adds a mode field:

# tests/pubsub/test.yaml — parallel execution
suite:
  name: parallel-pubsub
  mode: parallel
fixtures: [node]
timeout: 30

The mode field controls how members execute:

• sequential (default): members run one after another in lexicographic order.
• parallel: all members run concurrently on separate threads while sharing the same fixture lifecycle. Fixture assertions are serialized to maintain correctness. Use this when tests are independent and can safely share fixtures at the same time.

The plain string form (suite: smoke-http) is equivalent to suite: {name: smoke-http, mode: sequential}.

Key rules:

• Suites are directory-owned. Once a test.yaml sets suite, all descendants belong to that suite. Put tests that should remain independent outside the suite directory or in a sibling directory with a different suite.
• Per-test frontmatter may not declare suite.
• Suite members inherit the directory defaults and can still override most keys on a per-file basis. The exceptions are fixtures and retry, which must be defined at the directory level once a suite is active so every member agrees on the shared lifecycle. Outside suites you can still set those keys directly in frontmatter.
• Each suite occupies a single worker. Different suites (and standalone tests) can run in parallel when --jobs allows it.
• The CLI executes all suites before any remaining standalone tests so shared fixtures start and stop predictably.
• Run the directory that defines the suite (for example tenzir-test tests/http) when you want to focus on it. Selecting an individual member now raises an error so every run exercises the full lifecycle and shared fixtures stay in sync.

Inputs

Tests access input data through the TENZIR_INPUTS environment variable. By default this points to <root>/inputs or <package>/tests/inputs/ in package mode. The harness supports two additional mechanisms for placing inputs closer to the tests that use them.

Inline inputs

Place a .input file next to a test to provide test-specific input data. The harness exposes the file path via TENZIR_INPUT (singular):

tests/parsing/
  parse-csv.input      # Input data for this test
  parse-csv.tql        # Test file
  parse-csv.txt        # Expected output baseline

Access the inline input in TQL:

from_file env("TENZIR_INPUT")
read_csv

Or in a shell script:

cat "$TENZIR_INPUT" | tenzir 'read_csv'

The harness sets TENZIR_INPUT only when a matching .input file exists. Tests can use both TENZIR_INPUT and TENZIR_INPUTS together when they need a test-specific file plus access to shared data.

Local inputs directories

Place an inputs/ directory at any level in the test hierarchy to provide shared inputs for tests in that subtree. The harness walks up from each test directory and uses the nearest inputs/ directory it finds:

tests/
  network/
    inputs/               # Shared inputs for network tests
      sample.pcap
      flows.ndjson
    tcp/
      analysis.tql        # env("TENZIR_INPUTS") → ../inputs/
      analysis.txt
    udp/
      stats.tql
      stats.txt
inputs/                   # Global inputs (fallback)
  common.json

Resolution hierarchy for TENZIR_INPUTS:

1. inputs: override in test frontmatter or test.yaml (highest priority)
2. Nearest inputs/ directory walking up from the test directory
3. Package-level tests/inputs/ directory
4. Project-level inputs/ directory (fallback)

When multiple inputs/ directories exist in the hierarchy, the nearest one shadows the others. This keeps the mental model simple: move inputs closer to the tests that use them without worrying about inheritance.

Stdin inputs

Place a .stdin file next to a test to provide content that the harness pipes to the subprocess stdin. For TQL tests, this lets pipelines start with a parser directly as an alternative to using .input files with from_file:

tests/parsing/
  csv.stdin          # CSV data piped to stdin
  csv.tql            # Test file starting with read_csv
  csv.txt            # Expected output baseline

The TQL test reads directly from stdin:

read_csv
sort name

For shell scripts, the same mechanism applies:

tests/shell/
  echo.stdin         # Content piped to stdin
  echo.sh            # Test file
  echo.txt           # Expected output baseline

#!/bin/sh
cat

The harness pipes the contents of the .stdin file automatically. Tests can combine .stdin with .input when they need both stdin content and a test-specific input file:

tests/shell/
  process.stdin      # Content piped to stdin
  process.input      # Input file accessible via TENZIR_INPUT
  process.sh         # Test file
  process.txt        # Expected output baseline

A script using both mechanisms:

#!/bin/sh
echo "from stdin:"
cat
echo "from TENZIR_INPUT:"
cat "$TENZIR_INPUT"

The harness sets TENZIR_STDIN only when a matching .stdin file exists. TQL tests can also combine both mechanisms—start with a parser for stdin data while using env("TENZIR_INPUT") to reference additional files.

Run a subset of tests

Pass individual files or directories to run specific tests:

uvx tenzir-test tests/alerts/high-severity.tql

You can list multiple paths in a single invocation. tenzir-test wires every argument into the same runner and fixture registry, so you can mix scenarios from the project and external checkouts:

uvx tenzir-test tests/alerts ../contrib/plugins/*/tests

Filter tests by pattern

Use -m/--match to select tests by matching against their relative path. Bare strings default to substring matching, so you can write short keywords without glob syntax:

uvx tenzir-test -m mysql         # runs every test with "mysql" in its path
uvx tenzir-test -m connect       # runs every test with "connect" in its path

Patterns containing glob metacharacters (*, ?, [) still use fnmatch syntax, which is fully backwards-compatible:

uvx tenzir-test -m '*mysql*'             # equivalent to -m mysql
uvx tenzir-test -m 'tests/*/connect.tql' # glob with wildcard

Repeat the flag to match multiple patterns (logical OR):

uvx tenzir-test -m context -m create     # tests matching either substring

When you combine positional TEST paths with -m patterns, the harness runs only tests that satisfy both constraints (intersection):

uvx tenzir-test tests/integrations/ -m mysql  # only mysql tests under integrations/

If a matched test belongs to a suite (configured via test.yaml), all tests in that suite are included automatically so the shared fixture lifecycle stays intact.

Run multiple projects with one command

Pass additional project directories after --root to execute several projects in one go. Include --all-projects so the root executes next to its satellites. The directory given to --root acts as the root project; all other directories are treated as satellites:

uvx tenzir-test --root example-project --all-projects example-satellite

The harness prints a project listing before execution that identifies each project with a marker and path:

i found 3 projects
i   ■ test
i   □ ../contrib/plugins/context/test
i   □ ../contrib/plugins/packages/test

Marker semantics:

• Filled markers indicate the root project; empty markers indicate satellites.
• Squares (■ □) represent regular projects; circles (● ○) represent packages or libraries.

Satellite paths display relative to the root project, making projects with identical directory names distinguishable.

Key rules:

• The root project provides the baseline configuration (fixtures, runners, test.yaml defaults, inputs). Satellites layer their own fixtures and runners on top; duplicate names raise an error so conflicts surface early.
• Paths printed in the CLI summary are relative to the working directory. The harness announces each project before running it and lists the runner mix per project for quick insight.
• You can target subsets inside each project with additional positional arguments (tenzir-test --root main --all-projects secondary tests/smoke). When you skip --root entirely and only list satellite directories, the harness runs those satellites in isolation.
• Satellites keep their own tests/, inputs/, fixtures/, and runners/ folders. A root project can host shared assets that satellites reuse without duplication—for example, the example repository includes an example-satellite/ directory that consumes the xxd runner exported by the root project while defining a satellite-specific fixture.

To regenerate baselines while targeting a specific binary and project root:

TENZIR_BINARY=/opt/tenzir/bin/tenzir \
TENZIR_NODE_BINARY=/opt/tenzir/bin/tenzir-node \
uvx tenzir-test --root tests --update

Runners

Runner	Command/behavior	Input extension	Artifact
tenzir	tenzir -f <test>	.tql	.txt
python	Execute with the active Python runtime	.py	.txt
shell	sh -eu <test> via the harness helper	.sh	varies

Selection flow:

1. The harness chooses the first registered runner that claimed the file extension.
2. Default suffix mapping applies when no runner explicitly claims an extension: .tql → tenzir, .py → python, .sh → shell.
3. A runner: <name> frontmatter entry overrides the automatic choice.
4. If no runner claims the extension and none is specified in frontmatter, the harness fails with an error instead of guessing.

Shell runner

Place scripts (for example under tests/shell/) with the .sh suffix to run them under bash -eu via the shell runner. The harness also prepends <root>/_shell to PATH so project-specific helper binaries become discoverable. The runner captures stdout and stderr (like 2>&1) and compares the combined output with <test>.txt; run tenzir-test --update path/to/test.sh when you need to refresh the baseline.

Register custom runners in runners/__init__.py via tenzir_test.runners.register() or the @tenzir_test.runners.startup() decorator. Use replace=True to override a bundled runner or register_alias() to publish alternate names.

The runner guide contains a full example (XxdRunner).

Passthrough-aware subprocesses

When passthrough mode is active the harness streams stdout/stderr directly to the terminal and skips reference comparisons. Runner implementations can respect this automatically by spawning processes through tenzir_test.run.run_subprocess(...). The helper captures output when the harness needs it and inherits the parent descriptors otherwise. Pass force_capture=True when your runner must collect stdout even in passthrough mode. If you need to branch on the current behavior, call tenzir_test.run.get_harness_mode() or tenzir_test.run.is_passthrough_enabled().

The harness cycles between three internal modes:

• HarnessMode.COMPARE – default behavior; compare actual output with stored baselines.
• HarnessMode.UPDATE – engaged when you pass --update; runners should overwrite reference files.
• HarnessMode.PASSTHROUGH – enabled via -p/--passthrough; stream output directly without touching baselines.

get_harness_mode() returns the current enum value so custom runners can adapt logic if needed.

Configuration and frontmatter

tenzir-test merges configuration sources in this order (later wins):

1. Project defaults (test.yaml files, applied per directory).
2. Per-test frontmatter (YAML for .tql/.xxd, # key: value comments for Python and shell scripts).

Common frontmatter keys:

Key	Type	Default	Description
runner	string	by suffix	Runner name (tenzir, python, shell, custom).
fixtures	list	[]	Requested fixtures. Accepts bare names and structured options mappings.
timeout	integer (s)	30	Command timeout. (--coverage multiplies it by five.)
error	boolean	false	Expect a non-zero exit code.
skip	string or dict	unset	Mark tests as skipped. See skip configuration.
requires	mapping	unset	Capability requirements. See capability requirements. Directory-level only.
inputs	string	project	Override TENZIR_INPUTS for this directory or test.
assertions	mapping	{}	Post-test assertion payloads. See assertions.
retry	integer	1	Total attempt budget for flaky tests (see below).
package-dirs	list of strings	inherit	Directory-only; extra packages merged with CLI --package-dirs.

test.yaml files accept the same keys and apply recursively to child directories. A relative inputs: value resolves against the file that defines it, so inputs: ../data inside tests/alerts/test.yaml points at tests/data/. Frontmatter values follow the same rule and win over directory defaults. Adjacent tenzir.yaml files still configure the Tenzir binary; the harness appends --config=<file> automatically. The lookup keeps working even when you point the CLI at extra directories on the command line.

retry represents the total number of attempts the harness should make before declaring the test failed. Intermediate attempts stay quiet; the final outcome line includes attempts=N/M whenever the budget exceeds one. Keep the value small and treat it as a temporary guardrail while you fix the underlying flakiness.

Skip configuration

The skip key supports two forms:

String form marks the test (or every test in the directory) as unconditionally skipped. The value is the reason:

skip: "pending upstream fix"

Structured form conditionally skips tests when a runtime condition occurs. Use this when the suite depends on an external resource that may not be available in every environment:

skip:
  on: fixture-unavailable

The on field accepts the following values:

• fixture-unavailable — skip when a fixture raises FixtureUnavailable during initialization. See Fixture unavailability.
• capability-unavailable — skip when a required capability (declared via requires) is missing from the runtime environment.

You can combine multiple conditions by passing a list:

skip:
  on:
    - fixture-unavailable
    - capability-unavailable

When the triggering condition occurs and the suite carries the matching on value, all tests in the suite are marked as skipped with exit code 0. Without the opt-in configuration the exception propagates normally and causes a test failure.

The optional reason field provides additional context that is combined with the condition message in the skip output.

Capability requirements

The requires key declares capabilities that must be present for a suite to run. It is only allowed in directory-level test.yaml files. Currently, the only supported category is operators:

tests/gcs/test.yaml

suite: gcs-integration
requires:
  operators: [from_gcs, to_gcs]
skip:
  on: capability-unavailable
  reason: requires GCS operators

Before running the suite, the harness asks each runner to check the listed requirements. If any are missing and the suite carries skip: {on: capability-unavailable}, the tests are skipped. Without the skip opt-in, missing capabilities cause a hard failure with a message listing the missing entries.

Capability probes are runner-aware. Each runner implements its own check_requirements method. For example, the built-in TQL runner checks operators by querying plugins | where name == "<operator>". Custom runners can override this method to probe their own environment. Runners that do not implement capability probes report all requirement categories as unsupported, which raises a hard error.

Tenzir configuration files

• The harness inspects the directory that owns each test. If it finds tenzir.yaml, it appends --config=<path> to every invocation of the bundled tenzir/tql/diff runners. The path also seeds TENZIR_CONFIG unless you set that variable yourself. Custom runners that call the Tenzir binary should either use run.get_test_env_and_config_args(test) or honour the exported environment variables explicitly.
• The built-in node fixture uses the same discovery process and starts tenzir-node from the directory that owns the test file, so relative paths inside tenzir-node.yaml resolve against the test location. See the built-in node fixture section for precedence rules.
• This lets you keep one config for CLI-driven scenarios while passing a different config to the embedded node, for example to tweak endpoints or data directories independently.

Fixtures

Declaring fixtures

• List fixture names in frontmatter (fixtures: [node, http]). Entries can be bare strings or single-key mappings with structured options:

  # Bare names (backward compatible)
  fixtures: [node, http]
  
  # With structured options
  fixtures:
    - node:
        tls: true
        port: 8443
    - http
  
  # Mixed form
  fixtures:
    - node:
        tls: true
    - http

  Importing the project fixtures package is enough to register custom fixtures thanks to the side effects in fixtures/__init__.py.

• The harness encodes requests in TENZIR_TEST_FIXTURES and exposes helper APIs in tenzir_test.fixtures:

  • fixtures() – Read-only view of active fixtures. Attribute access is supported, e.g. fixtures().node returns True if the fixture was requested and raises AttributeError otherwise.
  • acquire_fixture("name") – Manual controller for the named fixture. Use it as a context manager for automatic start()/stop() or call those methods explicitly to interleave lifecycle steps and optional hooks (for example kill() or restart()).
  • require("name") – Assert that a fixture was requested.
  • Executor() – Convenience wrapper that runs Tenzir commands with resolved binaries and timeout budget.

Example use from a Python helper:

from tenzir_test.fixtures import Executor

executor = Executor()
result = executor.run("from_file 'inputs/events.ndjson' | where severity >= 5\n")
assert result.returncode == 0

Built-in node fixture

• Request the fixture with fixtures: [node]; the harness will start tenzir-node with the binaries discovered for the current test.
• Configuration precedence:
  1. TENZIR_NODE_CONFIG in the environment.
  2. A tenzir-node.yaml placed next to the test file (exported automatically).
  3. The Tenzir defaults (no config file).
• The node process inherits the test directory as its current working directory, letting tenzir-node.yaml reference files with relative paths (for example state/ or schemas/).
• Each controller reuses its state and cache directories across start()/stop() cycles. By default they live under the per-test scratch directory (TENZIR_TMP_DIR/tenzir-node-*) and are removed once the fixture context ends. Starting a fresh controller (for example in another test run) yields a brand-new workspace.
• The fixture reuses other inherited arguments (for example --package-dirs=…) but replaces any existing --config= flag so the node process always honours the chosen configuration file.
• Tests can read TENZIR_NODE_CLIENT_ENDPOINT, TENZIR_NODE_CLIENT_BINARY, TENZIR_NODE_CLIENT_TIMEOUT, TENZIR_NODE_STATE_DIRECTORY, and TENZIR_NODE_CACHE_DIRECTORY from the environment to connect to the spawned node and inspect its working tree.
• Pipelines launched by the bundled Tenzir runners automatically receive --endpoint=<value> when this fixture is active, so they talk to the transient node without additional wiring.
• CLI and node configuration are independent: configure the CLI with tenzir.yaml and drop a tenzir-node.yaml (or set TENZIR_NODE_CONFIG) only when the node needs custom settings.
• When tenzir-node fails to start, the fixture reports the exit code and stderr output, making it easier to diagnose startup failures.

Built-in docker-compose fixture

• Request the fixture with fixtures: [docker-compose] or pass structured options in test.yaml or frontmatter. The fixture manages Docker Compose services for the duration of the test or suite.
• The fixture requires docker compose (v2) on the host. When Docker Compose is not available, it raises FixtureUnavailable so tests can skip gracefully via skip: {on: fixture-unavailable}.
• Configuration uses three nested dataclasses: DockerComposeOptions (top level), DockerComposeWaitOptions (readiness polling), and DockerComposeDownOptions (teardown behavior).

Options reference

Top-level options (DockerComposeOptions):

Field	Type	Default	Description
file	string	""	Path to the Compose file, resolved relative to the test directory.
project_name	string	""	Compose project name. Auto-generated from the test file name when empty.
profiles	list of string	[]	Compose profiles to activate.
services	list of string	[]	Services to start. When empty, all services in the Compose file start.
env_file	string or null	null	Path to an env file passed to docker compose --env-file, resolved relative to the test.
env	dict	{}	Extra environment variables injected into the Compose process.
pull	string	"missing"	Image pull policy: missing, always, or never.
build	boolean	false	Pass --build to docker compose up.
wait	object	see below	Readiness polling settings.
down	object	see below	Teardown settings.
log_on_failure	boolean	true	Collect and attach Docker Compose logs when the fixture fails.

Wait options (DockerComposeWaitOptions):

Field	Type	Default	Description
timeout_seconds	float	120.0	Maximum time to wait for all services to be ready.
poll_interval_seconds	float	1.0	Interval between readiness checks.

Down options (DockerComposeDownOptions):

Field	Type	Default	Description
volumes	boolean	true	Remove volumes on teardown (--volumes).
remove_orphans	boolean	true	Remove orphan containers (--remove-orphans).
timeout_seconds	integer	20	Timeout for docker compose down (--timeout).

Example configuration

Minimal configuration in test.yaml:

suite: compose-demo
fixtures:
  - docker-compose:
      file: compose.yaml
skip:
  on: fixture-unavailable
  reason: requires docker compose

Full configuration with all options:

fixtures:
  - docker-compose:
      file: compose.yaml
      project_name: my-project
      profiles: [integration]
      services: [redis, postgres]
      env_file: compose.env
      env:
        COMPOSE_PARALLEL_LIMIT: 8
      pull: always
      build: true
      wait:
        timeout_seconds: 90
        poll_interval_seconds: 2.0
      down:
        volumes: true
        remove_orphans: true
        timeout_seconds: 30
      log_on_failure: true

Readiness detection

The fixture polls each container until it is ready. If a container defines a health check, the fixture waits for the healthy status. Otherwise, it falls back to checking that the container is in the running state. The wait.timeout_seconds setting controls how long the fixture waits before raising an error.

Exported environment variables

Once all services are running, the fixture exports the following variables to the test environment:

Variable	Description
DOCKER_COMPOSE_PROVIDER	Always docker.
DOCKER_COMPOSE_PROJECT_NAME	The Compose project name (explicit or auto-generated).
DOCKER_COMPOSE_FILE	Absolute path to the resolved Compose file.
DOCKER_COMPOSE_SERVICE_<NAME>_CONTAINER_ID	Container ID for the service. <NAME> is the uppercased, normalized service name.
DOCKER_COMPOSE_SERVICE_<NAME>_HOST	Always 127.0.0.1.
DOCKER_COMPOSE_SERVICE_<NAME>_PORT_<PORT>_<PROTO>	Host-mapped port for a specific container port and protocol (for example _PORT_6379_TCP).
DOCKER_COMPOSE_SERVICE_<NAME>_PORT	Shorthand for the single published port, set only when the service exposes exactly one port binding.

Service names are normalized to uppercase with non-alphanumeric characters replaced by underscores. For a service named redis, the prefix is DOCKER_COMPOSE_SERVICE_REDIS_.

Teardown

When the test (or suite) completes, the fixture runs docker compose down with the configured teardown options. Volumes are removed by default to avoid leaking state between test runs. The fixture always attempts teardown even when the test fails.

Registering fixtures

Implement fixtures in fixtures/ and register them with @tenzir_test.fixture(). Decorate a generator function, yield the environment mapping, and handle cleanup in a finally block:

from tenzir_test import fixture


@fixture()
def http():
    server = _start_server()
    try:
        yield {"HTTP_FIXTURE_URL": server.url}
    finally:
        server.stop()

@fixture also accepts regular callables returning dictionaries, context managers, or FixtureHandle instances for advanced scenarios.

The fixture guide demonstrates an HTTP echo server that exposes HTTP_FIXTURE_URL and tears down cleanly.

Fixture options

Fixtures can declare a frozen dataclass via options= on @fixture(). The harness constructs a typed instance from frontmatter values:

@dataclass(frozen=True)
class HttpOptions:
    port: int = 0

@fixture(options=HttpOptions)
def http() -> Iterator[dict[str, str]]:
    opts = current_options("http")  # HttpOptions instance
    ...

fixtures:
  - http:
      port: 9090

Bare names (fixtures: [http]) produce the dataclass defaults.

Note

Option fields can be nested dataclasses. The harness instantiates them recursively. See the fixture guide for a complete walkthrough.

Fixture unavailability

Fixtures can signal that they cannot provide their service by raising FixtureUnavailable during initialization (before yielding). This is useful when a fixture depends on an external tool or runtime that may not be present in every environment.

from tenzir_test.fixtures import FixtureUnavailable, fixture


@fixture()
def mysql():
    if not shutil.which("docker"):
        raise FixtureUnavailable("docker not found")
    # ... start container, yield env, cleanup ...

By default the exception propagates and causes a test failure. To convert it into a skip, add a structured skip entry to the suite’s test.yaml:

tests/mysql/test.yaml

suite: mysql-integration
fixtures: [mysql]
skip:
  on: fixture-unavailable
  reason: "needs container runtime"

When the fixture raises FixtureUnavailable and the suite carries this configuration, the harness marks every test in the suite as skipped (exit code 0) and logs the combined reason. Without the opt-in configuration the exception surfaces as a regular failure. See skip configuration for the full syntax of the skip key.

Container runtime helpers

The tenzir_test.fixtures.container_runtime module provides shared building blocks for fixtures that manage containers directly (without Docker Compose): runtime detection, detached container startup, readiness polling, and lifecycle management. The built-in docker-compose fixture uses these helpers internally.

See the create fixtures guide for a step-by-step walkthrough.

Assertions

The assertions frontmatter key holds post-test validation payloads. Each top-level key inside assertions identifies an assertion category. The harness evaluates assertions after the test succeeds but before teardown, so resources are still live when checks run. A raised exception fails the test.

Fixture assertions

Fixture assertions let a fixture verify what happened during the test. Declare payloads under assertions.fixtures.<name>:

assertions:
  fixtures:
    http:
      expected_request:
        count: 1
        method: POST
        path: /status/not-found
        body: '{"foo":"bar"}'

The harness constructs a typed instance from the fixture’s registered assertions dataclass and invokes its assert_test hook. Omitting the block skips the hook. For suite tests the hook runs after each member rather than once at the end.

The fixture guide walks through the full implementation.

Environment variables

tenzir-test recognises the following environment variables:

• TENZIR_TEST_ROOT – Default test root when --root is omitted.
• TENZIR_BINARY / TENZIR_NODE_BINARY – Override binary auto-detection. Supports multi-part commands like TENZIR_BINARY="uvx tenzir" or TENZIR_NODE_BINARY="docker exec container tenzir-node".
• TENZIR_INPUTS – Preferred data directory. Defaults to the nearest inputs/ directory walking up from the test, falling back to the project-level inputs folder. Reflects any inputs: override from test.yaml or frontmatter.
• TENZIR_INPUT – Path to the inline input file when a .input file exists next to the test. Not set otherwise.
• TENZIR_STDIN – Path to the stdin file when a .stdin file exists next to the test. The harness pipes this file’s content to the subprocess stdin. Not set otherwise.
• TENZIR_KEEP_TMP_DIRS – Keep per-test scratch directories (equivalent to --keep).
• TENZIR_TEST_DEBUG – Enable debug logging and verbose output (equivalent to --debug).

Binary resolution

The harness automatically detects tenzir and tenzir-node binaries using this precedence:

1. TENZIR_BINARY / TENZIR_NODE_BINARY environment variable (highest priority)
2. Local installation found via PATH lookup (shutil.which)
3. Fallback to uvx tenzir / uvx --from tenzir tenzir-node when uv is installed

Most users can run tenzir-test without any configuration. When uv is installed, the harness automatically uses uvx to fetch and run Tenzir on demand.

Environment variables support multi-part commands, allowing invocations like TENZIR_BINARY="uvx tenzir" or TENZIR_BINARY="docker exec node tenzir". The harness splits these values into argument lists using shell tokenization rules.

Fixtures often publish additional variables (for example TENZIR_NODE_CLIENT_*, TENZIR_NODE_STATE_DIRECTORY, TENZIR_NODE_CACHE_DIRECTORY, HTTP_FIXTURE_URL).

During execution the harness also adds transient variables such as TENZIR_TMP_DIR so tests and fixtures can create temporary artifacts without polluting the repository. Combine it with --keep (or TENZIR_KEEP_TMP_DIRS=1) when you need to inspect the generated files after a run.

Baselines and artifacts

Regenerate reference output whenever behavior changes intentionally:

uvx tenzir-test --update

--purge removes stale artifacts (diffs, temporary files). Keep generated .txt files under version control so future runs can diff against them.

Troubleshooting

• Missing binaries – The harness auto-detects binaries on PATH and falls back to uvx tenzir when uv is installed. If neither is available, set the TENZIR_BINARY and TENZIR_NODE_BINARY environment variables to point at your installation.
• Unexpected exits – Set error: true in frontmatter when a non-zero exit is expected.
• Skipped tests – Use skip: reason to document temporary skips; baseline files can stay empty. For fixture-dependent suites, use skip: {on: fixture-unavailable} so tests skip gracefully when a required tool is missing. For capability-dependent suites, combine requires with skip: {on: capability-unavailable}.
• Noisy output – Use --jobs 1 to serialize worker logs, and enable --debug (or set TENZIR_TEST_DEBUG=1) when you need to trace comparisons and fixture activity. Note that --debug automatically enables verbose output.

See Also

• Run tests
• Write tests
• Create fixtures
• Add custom runners
• Run fixtures