How thoroughly has Segregated Witness been tested?

Question

I've encountered claims that Segregated Witness was "not really tested" and is being "rushed".

It is my understanding that SegWit had been running on Elements for more than half a year already, and that it is currently being run on its own testnet.

• Has development of SegWit been rushed?
• What level of testing has been performed on Segregated Witness?
• Is it reasonable to expect SegWit to be sufficiently tested and ready for deployment in April?

Answer 1

I'd suggest starting here: https://bitcoincore.org/en/2015/12/23/capacity-increases-faq/. There's also a SegWit adoption page on the site somewhere.

Finally, this article has some details on recent testing: http://www.coindesk.com/bitcoin-scaling-segregated-witness-expected-launch/

Answer 2

Summarized from Bitcoin Core's Segregated Witness announcement:

• The original version of SegWit was implemented in April through June 2015 for the Elements Project. It has facilitated every transaction on the Elements-based sidechains since then.
• The new softfork-variant of SegWit moved to the multi-user testing stage in December 2015 by activating on the SegNet, a dedicated testnet.
• A pull-request was submitted in April 2016 to Bitcoin Core for review.
• Since May 2016 SegWit was enabled on the regular testnet facilitating tests in a mixed environment with non-upgraded wallets.
• At a meeting of twenty Bitcoin Core developers in May 2016 an in-person review of SegWit's code and test coverage was performed.
• An updated version building on the current state of Bitcoin Core's development was provided for final review in June 2016.

Altogether, the concept has been in development for fourteen months, and variants of SegWit have been in production and network testing for a year. The Bitcoin version has been rigorously tested for over six months. It received final review approval today and was merged to Bitcoin Core's master branch.

After all testing is successfully concluded, a release candidate including Segregated Witness will be released for broader testing by all types of users. Once a release candidate without known issues is found, it will be released and made ready for signaling.