public function testSubSet()
{
$coll2 = $this->coll->subset();
$this->assertEquals($this->coll, $coll2);
$this->assertSame($coll2->count(), 1);
$this->coll->add($this->testEntities[2]);
// check that $coll2 hasn't changed:
$this->assertSame($coll2->count(), 1);
$coll3 = $this->coll->subset(1);
$this->assertSame($coll3->count(), 1);
$this->assertEquals($coll3->getObjects()[0], $this->testEntities[1]);
$coll4 = $this->coll->subset(1, 1);
$this->assertSame($coll4->count(), 1);
$this->assertEquals($coll4->getObjects()[0], $this->testEntities[2]);
$coll5 = $this->coll->subset(null, 1);
$this->assertSame($coll4->count(), 1);
$this->assertEquals($coll4->getObjects()[0], $this->testEntities[2]);
}
