Wales have arrived in New Zealand with the first Test on 11 June.
Warren Gatland's side were defeated 27-13 by England before departing and Foster thinks it was a useful exercise.
"They'll be better for the hit out and whilst it may have cost them a player or two, I'm sure it benefited them as a group," he said.
Foster continued, "What I know of Warren is that they will come down really well prepared and with a really good understanding of what they have to do on the park."
Ospreys flanker Dan Lydiate has been ruled out of the New Zealand tour after injuring his shoulder in Sunday's defeat by England.
Cardiff Blues' uncapped 23-year-old open-side Ellis Jenkins has been added to the touring party.
New Zealand have called up six uncapped players for June's Test series against Wales, which begins at Auckland's Eden Park on Saturday, 11 June.
Steve Hansen's side host Wales in Wellington a week later on 18 June with the final Test taking place in Dunedin on 25 June.
New Zealand assistant coach Ian Foster says Wales will be well prepared for their three-Test series against the All Blacks after playing England.