@nullify/testing

testing

A tiny testing library designed for modern Javascript

Table of Contents

• Background
• Install
• Usage
• API
• Details/Thanks
• Maintainers
• Contributing
• License

Background

Writing tests should be just like writing any other code. When writing tests with @nullify/testing, test modules are simple standalone scripts. They can be run in NodeJS, browsers, on mobile devices, etc. There are no external test runners or special global variables to require. Simply import @nullify/testing, define your tests using APIs that are similar to other testing frameworks, and run the script "as is".

It will automatically run as a test suite!

Features

• No cli, external test runners, or global variables
• Minimal and fast API with zero dependencies
• Async/await and promise support
• Run suites serially or concurrently
• Supports timeouts at the suite and individual test level
• Browser support (thanks to ES modules)
• Use any assertion library you want (but comes with its own)
• Built with Typescript, and supports Typescript tests
• Coverage reporting tools "just work"

Install

npm i @nullify/testing

Usage

There are multiple alternative APIs to make using @nullify/testing as easy as possible. Each test "suite" is a self-contained test suite, with its own runner and "stack" of hooks. Hooks are scoped to a given suite, and possibly to a given group within a suite. Ideally, each suite is its own module, and can be auto-run on import. For more complex testing scenarios, it is possible to include multiple suites in a single module, or to use an "index" test script to import multiple test suites.

Tests within a suite are run serially. But, individual suites can be run concurrently. Concurrency is simply a function of how the test suite is run. If you export a "promised" suite from a module and await it before running the next, you have serial tests, otherwise, you'll have concurrent tests!

API

Suite as object

Import and create a new suite object. Tests can be awaited to support running multiple suites in series (or concurrently). Specify optional settings to control suite behavior, such as disabling console.log output, or auto-running the whole suite.

// one.test.js
import { Suite, assert } from "@nullify/testing";

const { test, end } = Suite.create("object");

test("one", () => {
  assert(true, "should pass");
});

// Export awaited promise to enable chain-able test suites!
export default await end;

A series of test suites like the above can be chained with:

// index.test.js
await import("one.test.js");
await import("two.test.js");
// or...
import("one.test.js").then(() => import("two.test.js"));

export {};

Alternatively, @nullify/testing comes with a tool to "collect" suites into a single run:

import { collect } from "@nullify/testing";

// Run suites in series
collect(
  await import("./one.test.js"),
  await import("./two.test.js"),
  await import("./three.test.js")
);

// Run suites concurrently
collect(
  import("./one.test.js"),
  import("./two.test.js"),
  import("./three.test.js")
);

Suite as class

Import and create a new test Suite. By default, a Suite will automatically run your tests on import. Suites also support chained methods for a concise test specification.

import { Suite, assert } from "@nullify/testing";

// Tests will auto-run when this module is imported/run
Suite.create("class")
  .beforeEach(() => {
    // Setup test here
  })
  .test("one", () => {
    assert(true, "should pass");
  })
  .afterEach(() => {
    // Cleanup test here
  });

Suite as function

Suites can be kept isolated within the same module, or across multiple (importable) modules. To make specifying multiple suites per module nicer (or at last, nicer looking), there is also a "functional" API that lets you to scope test methods to a single suite setup function:

import { suite, assert } from "@nullify/testing";

suite("func", ({ test, group, hooks }) => {
  test("one", () => {
    assert(true, "should pass");
  });

  group("group", () => {
    hooks.beforeAll(() => {
      // Group-specific test setup
    });
    test("two", () => {
      // This will fail!
      assert.deepStrictEqual(
        { this: "that", another: false },
        { this: "them", other: true }
      );
    });
  });
});

Take a look at src/api.test.ts for a comprehensive set of API examples.

Typescript support

Since suites are just scripts, simply run your script with Typescript support:

node --loader ts-node/esm file.test.ts

Test coverage

Most test coverage tools "just work", without any additional effort:

c8 node file.test.js

Browser support

Runs in any modern browser with ES module support. Simply import it and define your tests; no bundlers required. In fact, if you're viewing this README via https://carsonfarmer.github.io/testing/ or somewhere that allows <script/>, you can see the test results for the following "suite" in your developer console!

<script type="module">
  import { Suite, assert } from "https://unpkg.com/@nullify/testing";

  const suite = new Suite("example");
  suite.test("one", () => {
    assert(true, "should pass");
  });
</script>

Alternative APIs

To make migrating existing test suites over to @nullify/testing easier, the library comes with (a limited set of) built-in aliases for BDD style interfaces. Just include the imports and destructuring at the top of your test files, and you're pretty much good to go!

import { Suite, assert } from "@nullify/testing";

const { it, describe, before } = Suite.create("bdd");

describe("the main test", () => {
  let something: string = "";
  before(() => {
    something = "from nothing!";
  });
  it("should be strictly equal", () => {
    assert.strictEquals(something, "from nothing!");
  });
});

<script type="module" unsafe-inline> import { Suite, assert } from "https://unpkg.com/@nullify/testing/dist/mod.js"; const suite = new Suite("example"); suite.test("one", () => { assert(true, "should pass"); }); </script>

Details/Thanks

The @nullify/testing library borrows heavily from the Deno standard library testing module, the builtin Deno.test tooling, as well as node-test, and hooked. It is kept simple by only supporting ES modules, promises and async/await patterns, and a very limited and opinionated API. What this leads to is simpler tests that "just work".

Hooks are implemented using a last-in first-out (LIFO) stack (thanks hooked), and the built-in test runner is a simple ordered test registry that can be iterated over as an async iterable (thanks Deno). The built-in assertion library is borrowed directly from Deno with minimal changes (thanks again Deno). The main difference is in how objects are formatted for comparison. This library uses vanilla JSON.stringify behavior to keep things simple and compatible, but at the expense of twice as many calls to JSON.stringify (thanks Stackoverflow).

Maintainers

@carsonfarmer

Contributing

PRs accepted.

Small note: If editing the README, please conform to the standard-readme specification.

License

MIT © 2021 Carson Farmer