Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. ```ts import { assertEquals } from "jsr:@std/assert"; Deno.test({ name: "example test", fn() { assertEquals("world", "world"); }, }); Deno.test({ name: "example ignored test", ignore: Deno.build.os === "windows", fn() { // This test is ignored only on Windows machines }, }); Deno.test({ name: "example async test", async fn() { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); } }); ```

Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. ```ts import { assertEquals } from "jsr:@std/assert"; Deno.test("My test description", () => { assertEquals("hello", "hello"); }); Deno.test("My async test description", async () => { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); }); ```

Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. Declared function must have a name. ```ts import { assertEquals } from "jsr:@std/assert"; Deno.test(function myTestName() { assertEquals("hello", "hello"); }); Deno.test(async function myOtherTestName() { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); }); ```

Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. ```ts import { assert, fail, assertEquals } from "jsr:@std/assert"; Deno.test("My test description", { permissions: { read: true } }, (): void => { assertEquals("hello", "hello"); }); Deno.test("My async test description", { permissions: { read: false } }, async (): Promise => { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); }); ```

Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. ```ts import { assertEquals } from "jsr:@std/assert"; Deno.test( { name: "My test description", permissions: { read: true }, }, () => { assertEquals("hello", "hello"); }, ); Deno.test( { name: "My async test description", permissions: { read: false }, }, async () => { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); }, ); ```

Register a test which will be run when `deno test` is used on the command line and the containing module looks like a test module. `fn` can be async if required. Declared function must have a name. ```ts import { assertEquals } from "jsr:@std/assert"; Deno.test( { permissions: { read: true } }, function myTestName() { assertEquals("hello", "hello"); }, ); Deno.test( { permissions: { read: false } }, async function myOtherTestName() { const decoder = new TextDecoder("utf-8"); const data = await Deno.readFile("hello_world.txt"); assertEquals(decoder.decode(data), "Hello world"); }, ); ```