Manual: tap
RUN.JS(1) User Commands RUN.JS(1)
NAME
run.js - Test-Anything-Protocol module for Node.js
DESCRIPTION
Usage:
tap [options] []
tap v16.3.7 - A Test-Anything-Protocol library for JavaScript
Executes all the files and interprets their output as TAP formatted test result data. If no files are
specified, then tap will search for testy-looking files, and run those. (See '--test-regex' below.)
To parse TAP data from stdin, specify "-" as a filename.
Short options are parsed gnu-style, so for example '-bCRspec' would be equivalent to '--bail
--no-color --reporter=spec'
If the --check-coverage or --coverage-report options are provided explicitly, and no test files are
specified, then a coverage report or coverage check will be run on the data from the last test run.
Coverage is never enabled for stdin.
Much more documentation available at: https://www.node-tap.org/
Basic Options:
-R --reporter=
Use the specified reporter. Defaults to 'base' when colors are in use, or 'tap' when colors
are disabled.
In addition to the built-in reporters provided by the
treport and tap-mocha-reporter modules, the reporter option can also specify a command-line
program or a module to load via require().
Command-line programs receive the raw TAP output on
their stdin.
Modules loaded via require() must export either a
writable stream class or a React.Component subclass. Writable streams are instantiated and
piped into. React components are rendered using Ink, with tap={tap} as their only property.
Available built-in reporters: classic doc dot dump json
jsonstream landing list markdown min nyan progress silent spec tap xunit
-r --reporter-arg=
Args to pass to command-line reporters. Ignored when using built-in reporters or module reā
porters. Can be set multiple times
-F --save-fixture
Do not clean up fixtures created with t.testdir()
--no-save-fixture
switch off the --save-fixture flag
-b --bail
Bail out on first failure
-B --no-bail
Do not bail out on first failure (default)
--comments
Print all tap comments to process.stderr
--no-comments
switch off the --comments flag
-c --color
Use colors (Default for TTY)
-C --no-color
Do not use colors (Default for non-TTY)
-S --snapshot
Set to generate snapshot files for 't.matchSnapshot()' assertions.
--no-snapshot
switch off the --snapshot flag
-w --watch
Watch for changes in the test suite or covered program.
Runs the suite normally one time, and from then on,
re-run just the portions of the suite that are required whenever a file changes.
Opens a REPL to trigger tests and perform various
actions.
--no-watch
switch off the --watch flag
-n --changed
Only run tests for files that have changed since the last run.
This requires coverage to be enabled, because tap uses
NYC's process info tracking to monitor which file is loaded by which tests.
If no prior test run data exists, then all default
files are run, as if --changed was not specified.
--no-changed
switch off the --changed flag
-s --save= If exists, then it should be a line- delimited
list of test files to run. If is not present, then all command-line positional arguā
ments are run.
After the set of test files are run, any failed test
files are written back to the save file.
This way, repeated runs with -s will re-run
failures until all the failures are passing, and then once again run all tests.
Its a good idea to .gitignore the file used for this
purpose, as it will churn a lot.
-O --only
Only run tests with {only: true} option, or created with t.only(...) function.
--no-only
switch off the --only flag
-g --grep=
Only run subtests tests matching the specified pattern.
Patterns are matched against top-level subtests in each
file. To filter tests at subsequent levels, specify this option multiple times.
To specify regular expression flags, format pattern
like a JavaScript RegExp literal. For example: '/xyz/i' for case-insensitive matching.
Can be set multiple times
-i --invert
Invert the matches to --grep patterns. (Like grep -v)
-I --no-invert
switch off the --invert flag
-t --timeout=
Time out test files after seconds. Defaults to 30, or the value of the TAP_TIMEOUT enviā
ronment variable. Setting to 0 allows tests to run forever.
When a test process calls t.setTimeout(n) on the
top-level tap object, it also updates this value for that specific process.
-T --no-timeout
Do not time out tests. Equivalent to --timeout=0.
--files=
Alternative way to specify test set rather than using positional arguments. Supported as an
option so that test file arguments can be specified in .taprc and package.json files. Can be
set multiple times
Running Parallel Tests:
Tap can run multiple test files in parallel. This generally results in a speedier test run,
but can also cause problems if your test files are not designed to be independent from one anā
other.
To designate a set of files as ok to run in parallel, add them to a folder containing a file
named 'tap-parallel-ok'.
To designate a set of files as not ok to run in parallel, add them to a folder containing a
file named 'tap-parallel-not-ok'.
These folders may be nested within one another, and tap will do the right thing.
-j --jobs=
Run up to test files in parallel.
By default, this will be set to the number of CPUs on
the system.
Set --jobs=1 to disable parallelization entirely.
-J --jobs-auto
Run test files in parallel (auto calculated)
This is the default as of v13, so this option serves
little purpose except to re-set the parallelization back to the default if an earlier option
(or config file) set it differently.
--before=
A node program to be run before test files are executed.
Exiting with a non-zero status code or a signal will
fail the test run and exit the process in error.
--after=
A node program to be executed after tests are finished.
This will be run even if a test in the series fails
with a bailout, but it will *not* be run if a --before script fails.
Exiting with a non-zero status code or a signal will
fail the test run and exit the process in error.
Code Coverage Options:
Tap uses the nyc module internally to provide code coverage, so there is no need to invoke nyc
yourself or depend on it directly unless you want to use it in other scenarios.
--100 Enforce full coverage, 100%. Sets branches, statements, functions, and lines to 100.
This is the default. To specify a lower limit (or no
limit) set --lines, --branches, --functions, or --statements to a lower number than 100, or
disable coverage checking with --no-check-coverage, or disable coverage entirely with
--no-coverage.
-M --coverage-map=
Provide a path to a node module that exports a single function. That function takes a test
file as an argument, and returns an array of files to instrument with coverage when that file
is run.
This is useful in cases where a unit test should cover
a single portion of the system under test.
Return 'null' to not cover any files by this test.
Return an empty array [] to cover the set that nyc
would pull in by default. Ie, returning [] is equivalent to not using a coverage map at all.
--no-coverage-map
Do not use a coverage map. Primarily useful for disabling a coverage-map that is set in a conā
fig file.
-cov --coverage
Capture coverage information using 'nyc' This is enabled by default.
If a COVERALLS_REPO_TOKEN environment variable is set,
and the 'coveralls' module is installed, then coverage is sent to the coveralls.io service.
Note that tap does not automatically install coveralls,
it must already be present in your project to use this feature.
-no-cov --no-coverage
Do not capture coverage information. Note that if nyc is already loaded, then the coverage
info will still be captured.
--coverage-report=
Output coverage information using the specified istanbul/nyc reporter type.
Default is 'text' when running on the command line, or
'text-lcov' when piping to coveralls.
If 'html' is used, then the report will be opened in a
web browser after running.
This can be run on its own at any time after a test run
that included coverage.
Built-in NYC reporters: clover cobertura html json
json-summary lcov lcovonly none teamcity text text-lcov text-summary
Can be set multiple times
--no-coverage-report
Do not output a coverage report, even if coverage information is generated.
--browser
Open a browser when an html coverage report is generated. (this is the default behavior)
--no-browser
Do not open a web browser after generating an html coverage report
-pstree --show-process-tree
Enable coverage and display the tree of spawned processes.
--no-show-process-tree switch off the --show-process-tree flag
Coverage Enfocement Options:
These options enable you to specify that the test will fail if a given coverage level is not
met. Setting any of the options below will trigger the --coverage and --check-coverage flags.
The most stringent is --100. You can find a list of projects running their tests like this at:
https://www.node-tap.org/100
If you run tests in this way, please add your project to the list.
--check-coverage
Check whether coverage is within thresholds provided. Setting this explicitly will default
--coverage to true.
This can be run on its own any time after a test run
that included coverage.
--no-check-coverage
switch off the --check-coverage flag
--branches=
what % of branches must be covered?
--functions=
what % of functions must be covered?
--lines=
what % of lines must be covered?
--statements=
what % of statements must be covered?
Other Options:
-h --help
Show this helpful output
--no-help
switch off the --help flag
-v --version
Show the version of this program.
--no-version
switch off the --version flag
--test-regex= A regular expression pattern indicating tests to run if
no positional arguments are provided.
By default, tap will search for all files ending in
.ts, .tsx, .js, .jsx, .cjs, or .mjs, in a top-level folder named test, tests, or __tests__, or
any file ending in '.spec.' or '.test.' before a supported extension, or a top-level file
named 'test.(js,jsx,...)' or 'tests.(js,jsx,...)'
Ie, the default value for this option is:
((\/|^)(tests?|__tests?__)\/.*|\.(tests?|spec)|^\/?test s?)\.([mc]js|[jt]sx?)$
Note that .jsx files will only be run when --jsx is
enabled, .ts files will only be run when --ts is enabled, and .tsx files will only be run with
both --ts and --jsx are enabled.
--test-ignore=
When no positional arguments are provided, use the supplied regular expression pattern to exā
clude tests that would otherwise be matched by the test-regexp.
Defaults to '$.', which intentionally matches nothing.
Note: folders named tap-snapshots, node_modules, .git,
and .hg are ALWAYS excluded from the default test file set. If you wish to run tests in these
folders, then name the test files on the command line as positional arguments.
--test-arg=
Pass an argument to test files spawned by the tap command line executable. This can be speciā
fied multiple times to pass multiple args to test scripts. Can be set multiple times
--test-env=]>
Pass a key=value (ie, --test-env=key=value) to set an environment variable in the process
where tests are run.
If a value is not provided, then the key is ensured to
not be set in the environment. To set a key to the empty string, use --test-env=key=
Can be set multiple times
--nyc-arg=
Pass an argument to nyc when running child processes with coverage enabled. This can be speciā
fied multiple times to pass multiple args to nyc. Can be set multiple times
--node-arg=
Pass an argument to Node binary in all child processes. Run 'node --help' to see a list of
all relevant arguments. This can be specified multiple times to pass multiple args to Node.
Can be set multiple times
-gc --expose-gc
Expose the gc() function to Node.js tests
--debug
Turn on debug mode
--no-debug
switch off the --debug flag
--debug-brk
Run JavaScript tests with node --debug-brk
--harmony
Enable all Harmony flags in JavaScript tests
--strict
Run JS tests in 'use strict' mode
--flow Removes flow types
--no-flow
switch off the --flow flag
--ts Automatically load .ts and .tsx tests ts-node module. Note: you must provide ts-node as a deā
pendency yourself, tap does not automatically bundle it. (Default: false)
--no-ts
switch off the --ts flag
--jsx Automatically load .jsx tests using tap's bundled import-jsx loader (Default: false)
--no-jsx
switch off the --jsx flag
--nyc-help
Print nyc usage banner. Useful for viewing options for --nyc-arg.
--no-nyc-help
switch off the --nyc-help flag
--nyc-version
Print version of nyc used by tap.
--no-nyc-version
switch off the --nyc-version flag
--parser-version
Print the version of tap-parser used by tap.
--no-parser-version
switch off the --parser-version flag
--versions
Print versions of tap, nyc, and tap-parser
--no-versions
switch off the --versions flag
--dump-config
Dump the config options in YAML format
--no-dump-config
switch off the --dump-config flag
--rcfile=
Load any of these configurations from a YAML-formatted file at the path specified. Defaults to
.taprc in the current working directory.
Run 'tap --dump-config' to see available options and
formatting.
--libtap-settings=
A module which exports an object of fields to assign onto 'libtap/settings'. These are adā
vanced configuration options for modifying the behavior of tap's internal runtime.
Module path is resolved relative to the current working
directory.
Allowed fields: rmdirRecursive, rmdirRecursiveSync,
StackUtils, stackUtils, output, snapshotFile.
See libtap documentation for expected values and usage.
https://github.com/tapjs/libtap
-o --output-file=
Send the raw TAP output to the specified file. Reporter output will still be printed to stdā
out, but the file will contain the raw TAP for later replay or analysis.
-d --output-dir=
Send the raw TAP output to the specified directory. A separate .tap file will be created for
each test file that is run. Reporter output will still be printed to stdout, but the files
will contain the raw TAP for later replay or analysis.
Files will be created to match the folder structure and
filenames of test files run, but with '.tap' appended to the filenames.
-- Stop parsing flags, and treat any additional command line arguments as filenames.
Environment Variables:
COVERALLS_REPO_TOKEN
Set to a Coveralls token to automatically send coverage information to https://coveralls.io,
if the 'coveralls' module is installed in the project.
TAP_CHILD_ID
Test files have this value set to a numeric value when run through the test runner. It also
appears on the root tap object as `tap.childId`.
TAP_SNAPSHOT
Set to '1' to generate snapshot files for 't.matchSnapshot()' assertions.
TAP_RCFILE
A yaml formatted file which can set any of the above options. Defaults to ./.taprc
TAP_LIBTAP_SETTINGS
A path (relative to current working directory) of a file that exports fields to override the
default libtap settings
TAP_TIMEOUT
Default value for --timeout option.
TAP_COLORS
Set to '1' to force color output, or '0' to prevent color output.
TAP_BAIL
Bail out on the first test failure. Used internally when '--bailout' is set.
TAP Set to '1' to force standard TAP output, and suppress any reporters. Used when running child
tests so that their output is parseable by the test harness.
TAP_DIAG
Set to '1' to show diagnostics by default for passing tests. Set to '0' to NOT show diagnosā
tics by default for failing tests. If not one of these two values, then diagnostics are
printed by default for failing tests, and not for passing tests.
TAP_BUFFER
Set to '1' to run subtests in buffered mode by default.
TAP_DEV_LONGSTACK
Set to '1' to include node-tap internals in stack traces. By default, these are included only
when the current working directory is the tap project itself. Note that node internals are
always excluded.
TAP_DEBUG
Set to '1' to turn on debug mode.
NODE_DEBUG
Include 'tap' to turn on debug mode.
TAP_GREP
A '\n'-delimited list of grep patterns to apply to root level test objects. (This is an impleā
mentation detail for how the '--grep' option works.)
TAP_GREP_INVERT
Set to '1' to invert the meaning of the patterns in TAP_GREP. (Implementation detail for how
the '--invert' flag works.)
TAP_ONLY
Set to '1' to set the --only flag
TAP_TS Set to '1' to enable automatic typescript support
TAP_JSX
Set to '1' to enable automatic jsx support
Config Files:
You can create a yaml file with any of the options above. By default, the file at ./.taprc
will be loaded, but the --rcfile option or TAP_RCFILE environment variable can modify this.
Run 'tap --dump-config' for a listing of what can be set in that file. Each of the keys correā
sponds to one of the options above.
run.js 16.3.7 December 2025 RUN.JS(1)