@include test-module('_defaults') {
    @include test('should assign properties of a source object if missing on the destination object') {
        $value: ('a': 1);
        $defaults: ('a': 2, 'b': 2);
        $actual: _defaults($value, $defaults);
        $expected: ('a': 1, 'b': 2);

        @include assert-equal($actual, $expected);
    }

    @include test('should accept multiple source objects') {
        $expected: ('a': 1, 'b': 2, 'c': 3);
        $actual: _defaults(('a': 1, 'b': 2), ('b': 3), ('c': 3));

        @include assert-equal($actual, $expected);

        $actual: _defaults(('a': 1, 'b': 2), ('b': 3, 'c': 3), ('c': 2));

        @include assert-equal($actual, $expected);
    }

    // Differs from lodash -- must use 'null' to represent undefined values
    @include test('should overwrite null values') {
        $actual: _defaults(('a': null), ('a': 1));

        @include assert-equal(__get($actual, 'a'), 1);
    }

    @include test('should overwrite undefined values') {
        $actual: _defaults(('a': $__undefined__), ('a': 1));

        @include assert-equal(__get($actual, 'a'), 1);
    }
}