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Testing

Pun has a built-in test runner that supports TypeScript and hot reloading.

Writing Tests​

Create a file ending in .test.ts or .test.js.

import { test, expect, describe } from "pun:test";

describe("Math operations", () => {
  test("addition works", () => {
    expect(2 + 2).toBe(4);
  });

  test("arrays are equal", () => {
    expect([1, 2, 3]).toEqual([1, 2, 3]);
  });
});

Running Tests​

Run all tests in the project:

pun test

Run a specific test file:

pun test src/math.test.ts

Options​

  • --watch: Automatically rerun tests when files change.
  • --coverage: Generate a code coverage report.

Assertion API​

Pun's expect provides several matchers:

  • .toBe(value): Strict equality (===).
  • .toEqual(value): Deep equality.
  • .toBeGreaterThan(value)
  • .toBeLessThan(value)
  • .toThrow(error)
  • .rejects.toThrow(error)