Unfortunately the public test flights for Halo: The Master Chief Collection are not likely going to happen before E3 next month. Public flights were originally planned to begin at the end of April but was delayed due to quality concerns. In a new Reddit post community manager, Brian Jarrard, further explained the delay.
With E3 just being a few weeks away I can imagine all hands are on deck for the big show where a leak has shown that we will get more info for Halo: Infinite. The PC version of MCC is scheduled to begin release with Halo: Reach and each game will be added in in chronological order. No new info has yet been provided about when the public tests will be rescheduled to but hopefully E3 will shed some light! Are you planning to pick up MCC when it finally releases on PC?