deno test

Deno ships with a built-in test runner using the Deno.test() API. To learn how to write tests, see the Testing fundamentals guide. For assertions, see @std/assert and @std/expect.

Running tests Jump to heading

Run all tests in the current directory and subdirectories:

deno test

Run tests in specific files:

deno test src/fetch_test.ts src/signal_test.ts

Run tests matching a glob pattern:

deno test src/*.test.ts

Run tests whose name matches a string or pattern:

deno test --filter "database"
deno test --filter "/^connect.*/"

Skip type-checking:

deno test --no-check

Permissions Jump to heading

Tests run with the same permission model as deno run. Grant permissions for your test suite:

deno test --allow-read --allow-net

Watch mode Jump to heading

Re-run tests automatically when files change:

deno test --watch

Parallel execution Jump to heading

Run test files across multiple worker threads:

deno test --parallel

By default, --parallel uses the number of available CPUs. Use DENO_JOBS=<N> to control the number of threads:

DENO_JOBS=4 deno test --parallel

Code coverage Jump to heading

Collect coverage data and generate a report:

deno test --coverage

This writes raw coverage data to a coverage/ directory. To generate a summary from existing coverage data, use deno coverage:

deno coverage coverage/

You can also output an lcov report for use with external tools:

deno coverage --lcov coverage/ > coverage.lcov

Reporters Jump to heading

Choose an output format with --reporter:

deno test --reporter=dot
deno test --reporter=tap

Write a JUnit XML report for CI systems:

deno test --junit-path=report.xml

Randomize order Jump to heading

Shuffle the order tests run in to catch hidden dependencies between tests:

deno test --shuffle

Leak detection Jump to heading

Trace the source of leaked async operations, timers, or resources:

deno test --trace-leaks

Testing code in documentation Jump to heading

Evaluate code blocks in JSDoc and Markdown files as tests:

deno test --doc

See Testing code in docs for details.

Command line usage:

deno test [OPTIONS] [files]... [-- [SCRIPT_ARG]...]

Run tests using Deno's built-in test runner.

Evaluate the given modules, run all tests declared with Deno.test() and report results to standard output:

deno test src/fetch_test.ts src/signal_test.ts

Directory arguments are expanded to all contained files matching the glob {*_,*.,}test.{js,mjs,ts,mts,jsx,tsx} or **/__tests__/**:

deno test src/

Type checking options Jump to heading

--check<CHECK_TYPE>optional

Set type-checking behavior. This subcommand type-checks local modules by default, so adding --check is redundant If the value of "all" is supplied, remote modules will be included. Alternatively, the 'deno check' subcommand can be used.

--no-check<NO_CHECK_TYPE>optional

Skip type-checking. If the value of "remote" is supplied, diagnostic errors from remote modules will be ignored.

Dependency management options Jump to heading

--cached-only

Require that remote dependencies are already cached.

--frozen<BOOLEAN>optional

Error out if lockfile is out of date.

--import-map<FILE>

Load import map file from local file or remote URL.

--lock<FILE>optional

Check the specified lock file. (If value is not provided, defaults to "./deno.lock").

--no-lock

Disable auto discovery of the lock file.

--no-npm

Do not resolve npm modules.

--no-remote

Do not resolve remote modules.

--node-modules-dir<MODE>optional

Sets the node modules management mode for npm packages.

--reload, -r<CACHE_BLOCKLIST>optional

Reload source code cache (recompile TypeScript) no value Reload everything jsr:@std/http/file-server,jsr:@std/assert/assert-equals Reloads specific modules npm: Reload all npm modules npm:chalk Reload specific npm module.

--vendor<vendor>optional

Toggles local vendor folder usage for remote modules and a node_modules folder for npm packages.

Options Jump to heading

--allow-scripts<PACKAGE>optional

Allow running npm lifecycle scripts for the given packages Note: Scripts will only be executed when using a node_modules directory (--node-modules-dir).

--cert<FILE>

Load certificate authority from PEM encoded file.

--conditions<conditions>

Use this argument to specify custom conditions for npm package exports. You can also use DENO_CONDITIONS env var. .

--config, -c<FILE>

Configure different aspects of deno including TypeScript, linting, and code formatting. Typically the configuration file will be called deno.json or deno.jsonc and automatically detected; in that case this flag is not necessary.

--env-file<FILE>optional

Load environment variables from local file Only the first environment variable with a given key is used. Existing process environment variables are not overwritten, so if variables with the same names already exist in the environment, their values will be preserved. Where multiple declarations for the same environment variable exist in your .env file, the first one encountered is applied. This is determined by the order of the files you pass as arguments.

--ext<ext>

Set content type of the supplied file.

--hide-stacktraces

Hide stack traces for errors in failure test results.

--ignore<ignore>

Ignore files.

--location<HREF>

Value of globalThis.location used by some web APIs.

--minimum-dependency-age<minimum-dependency-age>

(Unstable) The age in minutes, ISO-8601 duration or RFC3339 absolute timestamp (e.g. '120' for two hours, 'P2D' for two days, '2025-09-16' for cutoff date, '2025-09-16T12:00:00+00:00' for cutoff time, '0' to disable).

--no-config

Disable automatic loading of the configuration file.

--parallel

Run test modules in parallel. Parallelism defaults to the number of available CPUs or the value of the DENO_JOBS environment variable.

--preload<FILE>

A list of files that will be executed before the main module.

--require<FILE>

A list of CommonJS modules that will be executed before the main module.

--seed<NUMBER>

Set the random number generator seed.

--v8-flags<V8_FLAGS>optional

To see a list of all available flags use --v8-flags=--help Flags can also be set via the DENO_V8_FLAGS environment variable. Any flags set with this flag are appended after the DENO_V8_FLAGS environment variable.

Debugging options Jump to heading

--inspect<HOST_PORT>optional

Activate inspector on host:port [default: 127.0.0.1:9229]. Host and port are optional. Using port 0 will assign a random free port.

--inspect-brk<HOST_PORT>optional

Activate inspector on host:port, wait for debugger to connect and break at the start of user script.

--inspect-wait<HOST_PORT>optional

Activate inspector on host:port and wait for debugger to connect before running user code.

Testing options Jump to heading

--clean

Empty the temporary coverage profile data directory before running tests. Note: running multiple deno test --clean`` calls in series or parallel for the same coverage directory may cause race conditions.

--coverage<DIR>optional

Collect coverage profile data into DIR. If DIR is not specified, it uses 'coverage/'. This option can also be set via the DENO_COVERAGE_DIR environment variable.

--coverage-raw-data-only

Only collect raw coverage data, without generating a report.

--doc

Evaluate code blocks in JSDoc and Markdown.

--fail-fast<N>optional

Stop after N errors. Defaults to stopping after first failure.

--filter<filter>

Run tests with this string or regexp pattern in the test name.

--junit-path<PATH>

Write a JUnit XML test report to PATH. Use '-' to write to stdout which is the default when PATH is not provided.

--no-run

Cache test modules, but don't run tests.

--permit-no-files

Don't return an error code if no files were found.

--reporter<reporter>

Select reporter to use. Default to 'pretty'.

--shuffle<NUMBER>optional

Shuffle the order in which the tests are run.

--trace-leaks

Enable tracing of leaks. Useful when debugging leaking ops in test, but impacts test execution time.

File watching options Jump to heading

--no-clear-screen

Do not clear terminal screen when under watch mode.

--watch<FILES>optional

Watch for file changes and restart process automatically. Local files from entry point module graph are watched by default. Additional paths might be watched by passing them as arguments to this flag.

--watch-exclude<FILES>optional

Exclude provided files/patterns from watch mode.

Running tests Jump to heading#

Permissions Jump to heading#

Watch mode Jump to heading#

Parallel execution Jump to heading#

Code coverage Jump to heading#

Reporters Jump to heading#

Randomize order Jump to heading#

Leak detection Jump to heading#

Testing code in documentation Jump to heading#

Type checking options Jump to heading#

Dependency management options Jump to heading#

Options Jump to heading#

Debugging options Jump to heading#

Testing options Jump to heading#

File watching options Jump to heading#

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