Hello.

I have a class which I have written some tests for, to ensure if I ever change some code it will still work as intended.

The documentation https://dlang.org/spec/unittest.html says it is can be placed both in the class or outside it.

I come from a background of having a completely separate tests folder with only tests, so I do not know what the general best-practice is with D. Where should the `unittest` code block go?

On 10/26/20 9:16 AM, Vladimirs Nordholm wrote:
> Hello.
> 
> I have a class which I have written some tests for, to ensure if I ever change some code it will still work as intended.
> 
> The documentation https://dlang.org/spec/unittest.html says it is can be placed both in the class or outside it.
> 
> I come from a background of having a completely separate tests folder with only tests, so I do not know what the general best-practice is with D. Where should the `unittest` code block go?

Wherever you want. Generally people put it right after the thing being tested to keep files organized.

When the compiler runs unittests it runs them all in the sequence they are in the file.

One place to be cautious though -- if you put them inside a template, they will be created for every instantiation of that template.

-Steve

On Monday, 26 October 2020 at 13:36:58 UTC, Steven Schveighoffer wrote:
> On 10/26/20 9:16 AM, Vladimirs Nordholm wrote:
>> [...]
>
> Wherever you want. Generally people put it right after the thing being tested to keep files organized.
>
> When the compiler runs unittests it runs them all in the sequence they are in the file.
>
> One place to be cautious though -- if you put them inside a template, they will be created for every instantiation of that template.
>
> -Steve

Thanks for the explanation (and the warning) Steve :)

On Monday, 26 October 2020 at 13:16:32 UTC, Vladimirs Nordholm wrote:
> Hello.
> [...]

Additionally, if you care about generating documentation, then placing them after whatever is being tested can make them end up as examples (of how to use them). Handy if your unittests shows how they're used and not only tests that they work; not so much otherwise.

class Foo
{
    /// asdf
    int multiplier;

    /++
        Multiplies stuff by `multiplier`.

        Params:
            n = Number to multiply.

        Returns:
            The integer passed, multiplied by `multiplier`.
     +/
    int mul(int n)
    {
        return multiplier * n;
    }

    ///
    unittest
    {
        // Will end up in examples section, provided /// is placed above unittest
        Foo foo = new Foo;
        foo.multiplier = 2;

        int four = foo.mul(2);
        int six = foo.mul(3);
        int eight = foo.mul(4);
        int ten = foo.mul(5);
    }
}

https://i.imgur.com/zjuJQkR.jpg

Even so I keep my larger test suite in a separate tests/ directory next to source/, but mostly because they'd swamp the original source files. You also lose the ability to unittest private stuff this way.