settings.md

Settings

Every DDTest setting can be passed as a CLI flag or as an environment variable. CLI flags take precedence over environment variables.

CLI flag	Environment variable	Env alias	Default	What it does
--platform	DD_TEST_OPTIMIZATION_RUNNER_PLATFORM		ruby	Language/platform. Currently supported: ruby, python.
--framework	DD_TEST_OPTIMIZATION_RUNNER_FRAMEWORK		rspec	Test framework. Currently supported: rspec, minitest, pytest.
--command	DD_TEST_OPTIMIZATION_RUNNER_COMMAND		""	Override the default base test command for supported framework modes. Currently used by RSpec and Minitest run/discovery, and Jest run; pytest ignores it. DDTest appends selected tests and framework-specific flags. For pytest, use PYTEST_ADDOPTS for pytest flags.
--min-parallelism	DD_TEST_OPTIMIZATION_RUNNER_MIN_PARALLELISM		physical CPU count	Minimum count DDTest considers when planning. Interpret it as CI nodes in CI-node mode, or workers in a single-node run.
--max-parallelism	DD_TEST_OPTIMIZATION_RUNNER_MAX_PARALLELISM		physical CPU count	Maximum count DDTest considers when planning. Interpret it as CI nodes in CI-node mode, or workers in a single-node run.
--ci-job-overhead	DD_TEST_OPTIMIZATION_RUNNER_CI_JOB_OVERHEAD		25s	Modeled overhead for adding one more CI node. Accepts durations such as 25s, 1m, 1500ms, or 0s to disable this bias. Increase it to use fewer CI nodes; decrease it to prefer faster wall time.
--target-time	DD_TEST_OPTIMIZATION_RUNNER_TARGET_TIME		0s	Target wall time for the selected split. Accepts durations such as 10m, 300s, 1500ms, or 0s to disable the target. DDTest first considers splits at or below this wall time; if none are possible within the min/max parallelism range, it warns and selects the split with the lowest expected wall time, ignoring CI job overhead, to get as close as possible to the target.
--ci-node	DD_TEST_OPTIMIZATION_RUNNER_CI_NODE		-1 (off)	Restrict this run to files assigned to CI node N (0-indexed).
--ci-node-workers	DD_TEST_OPTIMIZATION_RUNNER_CI_NODE_WORKERS		1	Number of workers to start on this CI node. Use a positive integer, or ncpu to use the node's available physical CPU cores.
--worker-env	DD_TEST_OPTIMIZATION_RUNNER_WORKER_ENV		""	Template env vars per worker: --worker-env "DATABASE_NAME_TEST=app_test{{nodeIndex}}_{{workerIndex}}". {{nodeIndex}} is the CI node index (0 for single-node runs); {{workerIndex}} is the worker process index within that CI node.
--tests-location	DD_TEST_OPTIMIZATION_RUNNER_TESTS_LOCATION	KNAPSACK_PRO_TEST_FILE_PATTERN	""	Custom glob pattern to discover test files, such as --tests-location "custom/spec/**/*_spec.rb" or --tests-location "tests/**/*_test.py". Defaults to spec/**/*_spec.rb for RSpec, test/**/*_test.rb for Minitest, and pytest config or **/{test_*,*_test}.py for pytest.
--tests-exclude-pattern	DD_TEST_OPTIMIZATION_RUNNER_TESTS_EXCLUDE_PATTERN	KNAPSACK_PRO_TEST_FILE_EXCLUDE_PATTERN	""	Glob pattern to exclude test files from discovery, such as --tests-exclude-pattern "spec/system/**/*_spec.rb".
--test-discovery-cache	DD_TEST_OPTIMIZATION_RUNNER_TEST_DISCOVERY_CACHE		""	Path to a restored test discovery cache file. DDTest imports it before planning and refreshes the internal discovery cache after successful full discovery.
--force-full-test-discovery	DD_TEST_OPTIMIZATION_RUNNER_FORCE_FULL_TEST_DISCOVERY		false	Force full test discovery when the framework supports it, including in suite-level skipping mode.
--strict-discovery	DD_TEST_OPTIMIZATION_RUNNER_STRICT_DISCOVERY		false	Fail planning when full test discovery fails. Cancelled full discovery still uses fast test file discovery fallback.
--runtime-tags	DD_TEST_OPTIMIZATION_RUNNER_RUNTIME_TAGS	DD_TEST_OPTIMIZATION_RUNTIME_TAGS	""	JSON string to override runtime tags used to fetch skippable tests. Useful for local development on a different OS than CI, such as --runtime-tags '{"os.platform":"linux","runtime.version":"3.2.0"}'.
	DD_TEST_OPTIMIZATION_RUNNER_REPORT_ENABLED		true	Print human-readable plan and run reports. Set to false to disable them.