documented unit tests as examples

[H. S. Teoh via Digitalmars-d]

On Sat, May 14, 2016 at 03:32:45PM +0200, Andrej Mitrovic via Digitalmars-d wrote:
[...]
> Add a new compiler switch (or better yet use a built-in version
> switch) which makes all assertions chatty.
> 
> So for a unittest like this:
> 
> ----
> auto sum (a, b) => a + b;
> 
> ///
> unittest { assert(sum(2, 2) == 4); }
> ----
> 
> Running it with something like this:
> 
> ----
> $ dmd -unittest -version=printasserts -run test.d
> ----
> 
> Would produce:
> 
> ----
> > test.d(4): assert(4 == 4); was successful
> ----
> 
> We could nitpick about the actual output, but the general idea is to
> avoid having to modify all the unittests by hand and instead use a
> compiler switch for chatty assertions.

I like this idea. But wouldn't it be too verbose? I.e., there may be a
lot of non-unittest-related assertions inside other functions and such.
We could say only top-level asserts in a unittest block become chatty,
but that excludes unittests calling unittest-only helper functions to do
the checks.


> And actually if we used a -version switch then I think we could
> implement this entirely in Druntime. That is unless I remember
> incorrectly how assertions are emitted, I haven't looked at the code
> in a while.

How would the assert implementation in druntime access the expression
being tested? I.e., in a way that it can be printed out in
human-readable form.


T

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