@function TestHas($a) {
  @return ('a': $a);
}
@include test-module('_has') {
  @include test('should check for own properties') {
    $map: ('a': 1);

    @include assert-equal(_has($map, 'a'), true);
    @include assert-equal(_has($map, 'b'), false);
  }

  @include test('should not check for inherited properties') {
    $map: __new(TestHas, ('a': 1));

    @include assert-equal(_has($map, '_type'), false);
    @include assert-equal(_has($map, 'a'), true);
  }

  @include test('should return false for non-maps') {
    @each $value in join($test-falsey, true 1 'a') {
      @include assert-equal(_has($value, 'a'), false);
    }
  }
}