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CLI ​

Main Commands ​

  • ast init
  • ast build
  • ast run
  • ast test
  • ast fuzz
  • ast doctor
  • ast clean

Common Examples ​

bash
ast test
ast test math,array
ast test math --suite array-check
ast test --parallel
ast test --mode node:wasi,node:bindings
ast test --list

ast fuzz
ast fuzz parser --runs 5000 --seed 42
ast fuzz parser --fuzzer parse-error --runs 1
ast fuzz parser --runs 1.5x
ast fuzz parser --runs +10%

ast doctor
ast clean
ast clean --mode node:wasi

Shared Flags ​

  • --config <path>
  • --mode <name[,name...]>
  • --list
  • --list-modes
  • --help

Modes with default: false are manual-only unless explicitly selected with --mode.

For ast clean, default: false is ignored. ast clean without --mode cleans every configured mode.

ast test ​

Important flags:

  • --browser <name|path>
  • --parallel
  • --jobs <n>
  • --build-jobs <n>
  • --run-jobs <n>
  • --create-snapshots
  • --overwrite-snapshots
  • --no-snapshot
  • --show-coverage
  • --show-coverage=all
  • --enable <feature>
  • --disable <feature>
  • --fuzz
  • --fuzz-runs <value>
  • --fuzz-seed <n> (pins seed; default is random per campaign)
  • --suite <name[,name...]>
  • --suites <name[,name...]>
  • --reporter <name|path>
  • --tap
  • --verbose
  • --clean
  • --watch (re-run on source or spec changes, 150ms debounced; Ctrl+C to stop)

Coverage notes:

  • --show-coverage prints uncovered coverage points
  • --show-coverage=all expands nested coverage gaps that are normally collapsed
  • --verbose also expands nested coverage gaps
  • dependency coverage is configured through coverage.mode and coverage.dependencies in config

ast fuzz ​

Important flags:

  • --runs <value>
  • --seed <n> (pins seed; default is random per campaign)
  • --fuzzer <name[,name...]>
  • --fuzzers <name[,name...]>
  • --suite <name[,name...]> (fuzz alias)
  • --suites <name[,name...]> (fuzz alias)
  • --jobs <n>
  • --build-jobs <n>
  • --run-jobs <n>

Unlike ast test, ast fuzz does not currently expose a --parallel shortcut flag. Use the job flags directly.

For fuzz commands, <value> can be an absolute count like 500, a multiplier like 1.5x, an additive percentage like +10%, or an additive integer like +100000.

ast init ​

Useful flags:

  • --dir <path>
  • --target wasi|bindings|web
  • --example minimal|full|none
  • --fuzz-example
  • --no-fuzz-example
  • --install
  • --yes
  • --force

ast clean ​

Behavior:

  • without --mode, ast clean removes configured build outputs, coverage outputs, crash artifacts, and logs for every configured mode
  • with --mode, clean stays scoped to the selected mode(s)
  • shared paths are skipped during scoped cleans unless every owning mode is selected

Examples:

  • ast clean
  • ast clean --mode node:wasi

Selectors ​

Selectors can be:

  • bare names resolved against configured input globs
  • explicit file paths
  • explicit globs
  • comma-separated bare names such as ast test math,array,string

Suite and fuzzer filters are separate from file selectors:

  • ast run math --suite array-check
  • ast run math --suite array-manipulation/array-check
  • ast fuzz parser --fuzzer parse-error
  • ast test --fuzz parser --fuzzers parse-error,serialize-roundtrip

Web Modes ​

For web targets, use --browser <name|path> or configure runOptions.runtime.browser.

Named browser values can be:

  • chrome
  • chromium
  • firefox
  • webkit

If no suitable browser is available, as-test can fall back to a Playwright-managed installation path.