Ask HN: Internal Transfers from Acquired Companies

Im currently doing e-commerce research within a company acquired by Google, but may be better situated in a different department located within the main campus. However I hear a rumor that there is a company policy which states that I would need to sit a coding interview before this would be allowed. Can anyone verify for/against this? I'm thinking it may be a bit hit or miss in terms of whether it routinely happens or not?

Note: This question applies specifically for Google, but Im interested in what other companies' practices are.