phobos unit tests

[H. S. Teoh via Digitalmars-d]

On Sat, Sep 03, 2016 at 05:46:23AM -0700, Jonathan M Davis via Digitalmars-d wrote:
> On Saturday, September 03, 2016 13:36:06 Manu via Digitalmars-d wrote:
> > This document: https://wiki.dlang.org/Contributing_to_Phobos
> >
> > States: "Avoid unittest in templates (it will generate a new
> > unittest for each instance) - put your tests outside"
> >
> > Sounds reasonable, but then I realised that most of my unit tests
> > are documenting unittests... this recommendation is in conflict with
> > the documentation standards... who wins?
> 
> Well, do you want everyone who ever uses your template to have your
> unit tests in their code? Yes, having ddoc unit tests is great, but I
> for one definitely don't think that it's worth having the unit tests
> inside of the templates, since they end up in everyone's code, and I'd
> strongly argue that no unit tests that aren't meant to be generic
> should ever be in templates so long as the language works this way.

	version(libraryBuild) { version = do_unittest; }
	version(libraryDocs) { version = do_unittest; }

	///
	struct S(T) {
		///
		void method() { ... }

		///
		unittest { /* generic test here */ }

		version(do_unittest)
		///
		unittest { /* non-generic test here */ }
	}


> That's why I created DIP 82:
> 
> http://wiki.dlang.org/DIP82
> 
> Unfortunately, it didn't generate much discussion and hasn't been
> implemented yet (which is often the case with DIPs), and now I need to
> figure out how to migrate it to the new DIP stuff on github and do
> that, or it's definitely not going anywhere. But I think that this is
> definitely a case where a language change is needed.

It would certainly be nice, I agree.  But there *are* ways of working
around this, even if they are a bit ugly (like above).


> In any case, for now, I never put non-generic unit tests in templates,
> and I reject PRs that have them. Sure, having to copy-paste your
> examples sucks, but it doesn't affect the code of everyone who uses
> the template, whereas ddoc-ed unit tests do.
[...]

Actually you don't need to copy-paste your examples, which IMO is a bad
idea to begin with. Just version out the non-generic unittests when
compiling user code, and you can have the best of both worlds.

In fact, versioning the unittests will also solve another problem: that
of not compiling library unittests when user code is being compiled with
-unittest (because the end user shouldn't need to bear the burden of
running unittests for the library just because they want to unittest
their own code).


T

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