Warn if integration using mocha/{test_unit,minitest} fails

[nitishr]

As suggested in #229

[floehopper]

Unfortunately #229 didn't really explain the issue thoroughly enough. I've updated the description of that issue to explain why we're not yet ready to apply the changes in this PR.

[floehopper]

Also I was imagining using Ruby's Kernel#warn directly since I don't think that strictly speaking this is a deprecation as such.

[nitishr]

Would it help if I changed the message from:

Deprecation.warning("MiniTest must be loaded *before* require 'mocha/minitest'.")

to

warn("MiniTest must be loaded *before* loading mocha.")

for minitest and a similar change for test-unit, i.e. not including the specific require statement (require mocha/minitest or require mocha/test_unit) in the warning message explicitly?

I think it'll be less/not confusing then, and will be more helpful than silence for someone whose test library integration has failed.

Even otherwise, I think it's more helpful to warn someone for whom the integration has failed than to avoid what a tiny (IMO) bit of confusion for someone who tried to integrate using the legacy/undocument require mocha/setup option.

[floehopper]

I'm away at the moment, but I'll look at this as soon as I get time. Sorry for the delay.

[floehopper]

I've belatedly realised that I was confused in my previous comments on this PR. I had confused mocha/test_unit.rb and mocha/minitest.rb with mocha/integration/test_unit.rb and mocha/integration/mini_test.rb. The former are not loaded/called by mocha/setup.rb whereas the latter are. I've updated #229 to reflect this (i.e. pretty much reverted it back to how it was). I've also created a new issue (#398) as a reminder to deprecate the use of "mocha/setup" which I now understand is a separate issue.

I also agree that it's sensible to use deprecation warnings in this PR as a first step; then as a later step we can fail fast. I don't know what I was thinking when I suggested using Kernel#warn.

Sorry for all the confusion. I will get this merged shortly.

[floehopper]

Tweaked very slightly and merged in c6032d0. Closing.