Re: [boost] [test] Interest in 'hamcrest'-style checks?

On Dec 29, 2013, at 1:04, Richard wrote:

[Please do not mail me a copy of your followup]

boost@lists.boost.org spake the secret code thusly:

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I recently read "Modern C++ Programming with Test-Driven Development", and I really enjoyed this book and highly recommend it.

I didn't know about this book until you posted this thread. I bought it and read it and loved it!

Yes, it's a terrific book!

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One of the styles I saw for the first time was "hamcrest"-style assertions. ("Hamcrest" is an anagram of "matchers"; also see http://en.wikipedia.org/wiki/Hamcrest.)

This is something that I don't think really buys us much in C++. The reason I say this is because in C++ we can take a macro argument and turn it into a string in order to produce a diagnostic message for the assert -- which Boost.Test does already.

In Java, you have no preprocessor and no way to do this, so Hamcrest style matchers are the way that they get the extra detail into the assertion messages.

Combine this ability of the preprocessor to take arbitrary program source text and turn it into a string and introduce a set of useful predicates for things like checking if a string starts with a prefix and you find the need for Hamcrest style matchers pretty much disappears.

Without the ability to turn source text into a string, the case for Hamcrest style matchers would increase dramatically. One area where I see Hamcrest style matchers being useful is in configuring mock objects. Having used jMock for Java and Turtle for Boost.Test/C++ I think both of them read fairly similar.

I put together a version of the Hamcrest matchers, and the only ones that I've ended up using are: * SameSequence -- I find the "equal collections" macro to be awkward (mainly due to the use of iterators) * SameSequenceAnyOrder -- when the order of the result is not known (or relevant); the custom error strings are very helpful here * FutureReady/FutureNotReady -- shorthand for "BOOST_CHECK_EQUAL(future.wait_for(...), std::future_status::ready/timeout)" But, it is very Java-esque, so I understand no one else was very excited about adding these. But, I figured I'd ask :) Jared

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