Save widget options as array

I’m using WP_Widget class and I have something like this in my form function:

<p>
			<label><?php _e('Test:') ?></label>
			<input type="text" name="<?php echo $this->get_field_name('test') ?>[]" class="widefat" />
			<input type="text" name="<?php echo $this->get_field_name('test') ?>[]" class="widefat" />
		</p>

Now, shouldn’t WP save the ‘test’ field as an array? When you use Options API it does, why this doesn’t work on widgets?