README

Basic test assertions expect(...)->toEqual('valid').

This package replaces and is inspired by fbexpect.

Usage

You pass the expression under test to expect(...) as the first argument. The returned object exposes some common assertions you'd want to make about a value, such as ->toEqual(). The simplest test you could write is:

expect(1 + 1)->toEqual(2);

Customization

If your assertion is not included in the basic set, fear not. You can create your own assertions object. Simply use the BasicAssertions trait in a class and add methods specific to your project to it. For example:

use namespace HH\Lib\Str;
use namespace HTL\Expect;

final class MyAssertions<T> {
  use Expect\BasicAssertions<T>;

  public function __construct(private T $value)[] {}

  <<__Override>>
  protected function getValue()[]: T {
    return $this->value;
  }

  public function toThrowMyDomainExpection<<<__Enforceable>> reify T>(
  )[]: void where {
    try {
      ($this->value)();
      throw new Expect\Surprise(
        'Expected a MyDomainException to be thrown, but no exception was thrown.'
      );
    } catch (\Exception $e) {
      if (!$e is T) {
        throw new Expect\Surprise(Str\format(
          'Expected a MyDomainException to be thrown, but got %s instead.',
          \get_class($e),
        ));
      }
    }
  }
}

Then create your own expect() function in your own namespace:

function expect(T $value)[]: MyAssertions<T> {
  return new MyAssertions($value);
}