API

To make the API available in scope, open the Test module:

Add_test.res

open Test

Basics

test

The test function identifies a test suite. You give it a name to easily find it in your output, and a function calling the assertions.

Add_test.res

test("Add", () => {  // Your assertions});

note

Nesting test suites is not allowed.

testAsync

testAsync works the same way, but gives the function an extra parameter, a done function to call when your test is done.

AsyncWorkflow_test.res

testAsync("Async workflow", (done) => {  // Your async assertions  done();});

Timeout

You can pass a timeout option that will make the tests fail if done hasn't been called by then:

AsyncWorkflow_test.res

testAsync("Async workflow", ~timeout=10, (done) => {  // Your async assertions  done()})

Planned assertions

If you want to make sure that your assertion count is right, you can pass the expected assertion count to the done function using a planned parameter. If your assertion count is different than what's planned, it'll make the suite fail.

AsyncWorkflow_test.res

testAsync("Async workflow", ~timeout=10, (done) => {  // Your async assertions  done(~planned=3, ())})

Setup and teardown

Setup & Teardown can be crucial in testing if you want to avoid having side effects from certain tests leak to other ones, or if you have logic that you want to share (e.g. setup React containers).

The API we provide is pretty similar to test & testAsync, they're nearly the same functions but with extra tweaks:

• A setup function that lets your return a value (see it as a test context)
• A teardown function that takes the value and lets you act on it
• value that's passed to your test function body

createTestWith

SetupAndTeardown_test.res

let setup = () => {  let element = document["createElement"](. "div")  document["body"]["appendChild"](. element)  element}
let teardown = element => {  element["remove"](. )}
const testWithElement = createTestWith(~setup, ~teardown)
testWithElement("Setup & teardown", (element) => {  // Your assertions that use `element`})

For a good reusability, we can take advantage of auto-currying:

TestUtils.res

let setup = () => {  let element = document["createElement"](. "div")  document["body"]["appendChild"](. element)  element}
let teardown = element => {  element["remove"](. )}
let testWithElement = testWith(~setup, ~teardown)

And reuse it across your tests!

SomeDOMTests_test.res

testWithElement("Some DOM logic", (element) => {  // Your assertions that use `element`});

createTestAsyncWith

Pretty much the same story there, expect we have the extra done argument

TestUtils.res

let setup = () => {  let element = document["createElement"](. "div")  document["body"]["appendChild"](. element)  element}
let teardown = element => {  element["remove"](. )}
let testWithElement = createTestAsyncWith(~setup, ~teardown)

And there we go:

SomeDOMTests_test.res

testAsyncWithElement("Some DOM logic", (element, done) => {  // Your async assertions that use `element`  done();});