The second review of SE-0019 "Swift Testing" for the Swift Package Manager ran from Jan. 15th-19th, 2016. The proposal has been accepted. Support for the initial proposal was positive on the concept but mixed on the details, and the proposal was revised accordingly; the second review has received limited comments, but the comments were positive. Apple will start committing implementation for this proposal soon, though community pull requests are welcome; please discuss this on email@example.com if you'd like to help with the implementation.
The accepted review can be found at https://github.com/apple/swift-evolution/blob/master/proposals/0019-package-manager-testing.md.
This initial proposal includes support for using XCTest; we expect that adding generic support for other testing frameworks will be discussed in an upcoming proposal.
Thank you all for your comments.