Ask HN: Simple Project Scheduling Software?

I'm currently doing a 6-month project for a client.

We want to simply create a schedule where I put each component of the project, how long it will take estimated, including hopefully some sort of beta testing/fixing time.

Then I give the software a start date and it will spit out a schedule.

Then when things change/go wrong/go right in the future, I should be able to change a date or a duration, and it will re-calculate my dates.

Does anyone know of this sort of software?