public function testKey()
{
$key = $this->datastore->key('Foo', 'Bar');
$this->assertInstanceOf(Key::class, $key);
$this->assertEquals($key->keyObject()['path'][0]['kind'], 'Foo');
$this->assertEquals($key->keyObject()['path'][0]['name'], 'Bar');
$key = $this->datastore->key('Foo', '123');
$this->assertEquals($key->keyObject()['path'][0]['kind'], 'Foo');
$this->assertEquals($key->keyObject()['path'][0]['id'], '123');
$key = $this->datastore->key('Foo', 123);
$this->assertEquals($key->keyObject()['path'][0]['kind'], 'Foo');
$this->assertEquals($key->keyObject()['path'][0]['id'], '123');
}