deno-test

Run Deno-style tests with Node.js.

deno-test lets you use Deno.test and t.step in your test files and run them on Node.js via npx. It resolves Deno-style imports (jsr:, @std/*, import maps) and supports TypeScript out of the box.

Tip: This is especially useful for verifying Node.js compatibility of packages developed Deno-first. Run your existing Deno tests on Node.js without rewriting them.

Install

npm i -D deno-test

Usage

npx deno-test [options] [files/dirs...]

Options

| Option | Description | | --- | --- | | --filter <string> | Run only tests whose name contains the given string | | -h, --help | Show help message |

Test file patterns

When no files are specified, deno-test auto-discovers test files in the current directory (recursively) matching these patterns:

• *_test.{ts,tsx,js,jsx,mts,mjs}
• *.test.{ts,tsx,js,jsx,mts,mjs}
• test.{ts,tsx,js,jsx}

Directories named node_modules, .git, and vendor are skipped.

Examples

# Run all test files in current directory
npx deno-test

# Run all test files in a specific directory
npx deno-test test/

# Run a single test file
npx deno-test test/math_test.ts

# Filter tests by name
npx deno-test --filter "add"

# Combine filter with directory
npx deno-test --filter "add" test/

Writing tests

Write tests using Deno.test just like you would for Deno:

import { assertEquals } from "@std/assert";

Deno.test("addition", () => {
  assertEquals(1 + 1, 2);
});

Deno.test("nested steps", async (t) => {
  await t.step("step 1", () => {
    assertEquals(2 * 2, 4);
  });

  await t.step("step 2", () => {
    assertEquals(3 * 3, 9);
  });
});

Import maps and jsr: specifiers work via deno.json:

{
  "imports": {
    "@std/assert": "jsr:@std/assert@^1.0.19"
  }
}

How it works

1. The CLI discovers test files and spawns Node.js with a custom module resolution hook (register-deno-hooks.mjs) that handles Deno-style imports using @deno/loader.
2. Test files are imported and Deno.test() calls are collected via @deno/shim-deno-test.
3. Collected tests are registered with Node.js's built-in node:test runner, with t.step() mapped to node:test's subtests.

Requirements

• Node.js >= 23.6.0

Note: This tool uses module.registerHooks(), a synchronous module resolution hook API added in Node.js 23.6.0.

License

MIT