stretchr/testify ? reverse-engineered prompt

Build me a Go testing helper library that makes writing tests feel a lot easier and more readable. I want simple assertions for common things like equals, not equals, nil, true, false, errors, and comparisons, with clear failure messages that show up nicely in normal Go tests.

It should also include a stricter version that stops the test right away when something fails, plus a lightweight way to create mock objects, set expectations on calls, and verify that those calls actually happened. If possible, add a clean way to organize related tests into reusable suites so bigger test setups are less repetitive.

Make it work naturally with the standard testing package, keep the API friendly and easy to remember, and include a few good examples so it’s obvious how to use it. If you need to check current Go testing patterns or docs online, feel free to look them up.