Unit test practices in Phobos

[Andrei Alexandrescu]

Jeremie Pelletier wrote:
> Andrei Alexandrescu Wrote:
> 
>> Jeremie Pelletier wrote:
>>> Lars T. Kyllingstad Wrote:
>>>
>>>> I just filed a bug report (3240) that describes a case where IFTI is 
>>>> used in Phobos, and where this causes errors when the function is used 
>>>> with a different type than the one used in the unittest. (The well known 
>>>> "IFTI doesn't work with implicit conversions" problem.) I have a strong 
>>>> suspicion that there are many other cases like this waiting to be 
>>>> discovered.
>>>>
>>>> I have encountered such errors in my own code many times, and lately 
>>>> I've been trying to get into the habit of writing unittests for all (or 
>>>> at least more than one) types. Not full-fledged functionality tests, 
>>>> mind you -- something like this is usually sufficient:
>>>>
>>>>    T foo(T)(T x) if (isFloatingPoint!T) { return x + 1.0; }
>>>>
>>>>    unittest
>>>>    {
>>>>        // Test different types
>>>>        alias foo!float foo_float;
>>>>        alias foo!double foo_double;
>>>>        alias foo!real foo_real;
>>>>
>>>>        // Test functionality
>>>>        assert (foo(2.0) == 3.0);
>>>>    }
>>>>
>>>> For the cases where any type is allowed (or a lot of them, at least) 
>>>> even this can become a time-consuming task. In these cases it should at 
>>>> least be possible to make a representative selection of types to check.
>>>>
>>>> I just wanted to recommend this as "good practice" to all, but 
>>>> especially to the Phobos authors. In my experience this catches a lot of 
>>>> bugs which are otherwise hard to spot.
>>>>
>>>> -Lars
>>> I just go with type tuples:
>>>
>>> T foo(T)(T x) if(isFloatingPoint!T) { return x + 1.0; }
>>> unittest {
>>>     foreach(T; allFloatingPointTuple) assert(foo!T(1.0) == 2.0);
>>> }
>> Yah, same here. I have unit tests in Phobos that have nested loops 
>> testing against so many types, the release build takes forever. Some 
>> edge case for the optimizer. I must disable them in release builds.
>>
>>
>> Andrei
> 
> Don't you disable unittests in release builds?

Phobos has the builds: debug, release, unittest/debug, and 
unittest/release. Client apps use the release version. I like being able 
  to unittest the release version to make sure that the optimizer etc. 
don't do shenanigans.

Andrei