public function testUnionWithArrays()
{
$A = new Set([1, 2, [1, 2, 3]]);
$B = new Set([2, 3, [2, 3, 4]]);
$A∪B = $A->union($B);
$expected = new Set([1, 2, [1, 2, 3], 3, [2, 3, 4]]);
$this->assertEquals($expected, $A∪B);
$this->assertEquals($expected->asArray(), $A∪B->asArray());
$A = new Set([1, 2, [1, 2, 3]]);
$B = new Set([2, 3, [2, 3, 4], [1, 2, 3]]);
$A∪B = $A->union($B);
$expected = new Set([1, 2, [1, 2, 3], 3, [2, 3, 4]]);
$this->assertEquals($expected, $A∪B);
$this->assertEquals($expected->asArray(), $A∪B->asArray());
}