ReScriptTest

> A lightweight test framework for ReScript

Check out the documentation!

Installation

Run the following in your console:

``console
$ yarn add --dev rescript-test
`

Then add rescript-test to your bsconfig.json's bs-dev-dependencies:

`diff
{
"bs-dev-dependencies": [
+ "rescript-test",
]
}
`

Usage

`console
$ # All tests
$ retest 'test/*/.bs.js'
$ # Single file
$ retest 'test/MyTest.bs.js'
`

Testing with DOM

The test framework can simulate a browser using JSDOM, to activate it, simply add the --with-dom option.

`console
$ # All tests
$ retest --with-dom 'test/*/.bs.js'
$ # Single file
$ retest --with-dom 'test/MyTest.bs.js'
`

Basics

`rescript
open Test

let intEqual = (~message=?, a: int, b: int) =>
assertion(~message?, ~operator="intEqual", (a, b) => a === b, a, b)

let stringEqual = (~message=?, a: string, b: string) =>
assertion(~message?, ~operator="stringEqual", (a, b) => a == b, a, b)

test("Equals", () => {
let a = 1
let b = 1
intEqual(a, b)
})

let isCharCode = (a, b) => {
a->String.charCodeAt(0) === b
}

test("Custom comparator", () => {
let a = "a"

assertion(~message="Char code should match", ~operator="isCharCode", isCharCode, a, 97.0)
assertion(~message="Char code should match", ~operator="isCharCode", isCharCode, a, 98.0)
})

type user = {username: string, id: string}

let userEq = (a, b) => a.id === b.id
let userEqual = (~message=?, a: user, b: user) =>
assertion(~message?, ~operator="userEqual", userEq, a, b)

test("DeepEquals", () => {
let a = {username: "user", id: "a"}
let b = {username: "user", id: "a"}
stringEqual(a.username, b.username)
userEqual(a, b)
})
`

Outputs:

`sh
1/4: Equals
PASS - No message
2/4: Custom comparator
PASS - Char code should match
FAIL - Char code should match
---
operator: isCharCode
left: a
right: 98
...
3/4: DeepEquals
PASS - No message
PASS - No message
4/4: Async
PASS - No message

Ran 4 tests (6 assertions)

3 passed

1 failed

`

API

$3

- test(name, body)
- createTestWith(~setup: unit => 'a, ~teardown: 'a => unit=? -> test
- testAsync(name, body)
- createTestAsyncWith(~setup: unit => 'a, ~teardown: 'a => unit=?, name, body: ('a, cb) => unit) -> testAsync

$3

- throws(func, ~message: string=?, ~test: exn => bool=?)
- doesNotThrow(func, ~message: string=?)
- assertion(comparator, a, b, ~operator: string=?, ~message: string=?)
- pass()
- fail()
- todo(string)

$3

`rescript
let stringMapEqual = (~message=?, a, b) =>
assertion(
~message?,
~operator="stringMapEqual",
(a, b) => Belt.Map.String.eq(a, b, (a, b) => a === b),
a,
b,
)
`

Generic equal/deepEqual (not recommended)

Those that be useful to transition from an existing testing library, but we do not recommend polymorphic checks.

`reason
let equal = (~message=?, a, b) => assertion(~message?, ~operator="equal", (a, b) => a === b, a, b)

let deepEqual = (~message=?, a, b) =>
assertion(~message?, ~operator="deepEqual", (a, b) => a == b, a, b)
`

$3

The setup function returns a clean context for the test, the teardown function resets it.

`rescript
let testWithRef = createTestWith(~setup=() => ref(0), ~teardown=someRef => someRef := 0)

testWithRef("Setup & teardown", someRef => {
incr(someRef)
equal(someRef.contents, 1)
})
`

If you want to test with React, you can add the following helper as your test utility file:

`rescript
@bs.val external window: {..} = "window"
@bs.send external remove: Dom.element => unit = "remove"

let createContainer = () => {
let containerElement: Dom.element = window["document"]"createElement"
let _ = window["document"]["body"]"appendChild"
containerElement
}

let cleanupContainer = container => {
ReactDOM.unmountComponentAtNode(container)
remove(container)
}

let testWithReact = createTestWith(~setup=createContainer, ~teardown=cleanupContainer)
let testAsyncWithReact = createTestAsyncWith(~setup=createContainer, ~teardown=cleanupContainer)
`

And then use it:

`rescript
testWithReact("Can render", container => {
act(() =>
ReactDOMRe.render(


,
container,
)
)

let div = container->DOM.findBySelectorAndTextContent("div", "hello")
isTrue(div->Option.isSome)
})
`

$3

`rescript
testAsync("My test", (cb) => (
// your tests
cb(~planned=2, ())
))
`

$3

Add a retest.env.js` to your project root directory for any setup.