public function test_get_changed_keys()
 {
     $array_one = array('one' => 'foo', 'two' => array('a' => 'alpha', 'b' => 'beta'));
     $array_two = $array_one;
     $this->assertEmpty($this->connector->get_changed_keys($array_one, $array_two));
     $array_two['one'] = 'bar';
     $array_two['two']['a'] = 'aleph';
     $this->assertEquals(array('one', 'two'), $this->connector->get_changed_keys($array_one, $array_two));
     $this->assertEquals(array('one', 'two', 'two::a'), array_keys($this->connector->get_changed_keys($array_one, $array_two, 1)));
 }