public function testRemove()
 {
     $map = new ArrayOrderedMap();
     $map->insert('Alpha', 42);
     $value_to_remove = new \stdClass();
     $map->insert('Beta', $value_to_remove);
     $map->insert('Gamma', 200);
     list($value, $pos) = $map->remove('Beta');
     $this->assertSame($value_to_remove, $value);
     $this->assertEquals(1, $pos);
     $this->setExpectedException(KeyNotFoundException::class);
     $map->remove('DoesntExist');
 }