Define tests with a Jest-like API imported from the built-in bun:test module. Long term, Bun aims for complete Jest compatibility; at the moment, a limited set of expect matchers are supported.
Basic usage
To define a simple test:
import { expect, test } from "bun:test";
test("2 + 2", () => {
expect(2 + 2).toBe(4);
});
Jest-style globals
Tests can be grouped into suites with describe.
import { expect, test, describe } from "bun:test";
describe("arithmetic", () => {
test("2 + 2", () => {
expect(2 + 2).toBe(4);
});
test("2 * 2", () => {
expect(2 * 2).toBe(4);
});
});
Tests can be async.
import { expect, test } from "bun:test";
test("2 * 2", async () => {
const result = await Promise.resolve(2 * 2);
expect(result).toEqual(4);
});
Alternatively, use the done callback to signal completion. If you include the done callback as a parameter in your test definition, you must call it or the test will hang.
import { expect, test } from "bun:test";
test("2 * 2", done => {
Promise.resolve(2 * 2).then(result => {
expect(result).toEqual(4);
done();
});
});
Skip individual tests with test.skip. These tests will not be run.
import { expect, test } from "bun:test";
test.skip("wat", () => {
// TODO: fix this
expect(0.1 + 0.2).toEqual(0.3);
});
Mark a test as a todo with test.todo. These tests will be run, and the test runner will expect them to fail. If they pass, you will be prompted to mark it as a regular test.
import { expect, test } from "bun:test";
test.todo("fix this", () => {
myTestFunction();
});
Matchers
Bun implements the following matchers. Full Jest compatibility is on the roadmap; track progress here.