When is a phobos unittest supposed to be qualified with version (StdUnittest)? Ideally, always? I don't see that their current use is consistenly following a rule. If so, is the purpose of its presence to reduce the burden of the compiler when the application using phobos is compiled with -unittest? (edited).

If we were to put a version (StdUnittest) in front of every unittest in phobos (via an automated refactoring of course) would that speed building large applications or tests-suites with the -unittest flag provide they import many/all phobos libraries via, for instance, import std?

When compiling non-phobos modules with -unittest flag, how are the unittest-blocks in imported phobos modules processed by the compiler? Are they only lexed (and parsed) but nothing else?

On Saturday, 4 September 2021 at 00:09:37 UTC, H. S. Teoh wrote:

Well, no; it compiles all unittests of all compiled modules, not all imported modules. So it does not actually include Phobos unittests.

The point of StdUnittest is to suppress

• version (unittest) blocks in Phobos
• Phobos unittests in the bodies of templates that are instantiated by user code

As Steven Schveighoffer pointed out, Phobos unittests are never included in user code, regardless of whether StdUnittest is used.

On Friday, 3 September 2021 at 23:39:44 UTC, Per Nordlöw wrote:

Almost never.

version (StdUnittest) should be used in Phobos wherever you would normally use a version (unittest) block. It is not for the tests themselves, but for test fixtures and support code.

On Saturday, 4 September 2021 at 03:18:01 UTC, Paul Backus wrote:

Yes, but they are lexed and parsed, right?

On Saturday, 4 September 2021 at 03:18:01 UTC, Paul Backus wrote:

The "never" is false, https://d.godbolt.org/z/c4oeYM7rG

Unittests inside template code will be added to user code, unless the compiler has determined that the template is already instantiated in Phobos code (the "template culling" that the frontend does, whose behavior is not easily influenced by the programmer).

-Johan

On Saturday, 4 September 2021 at 09:42:46 UTC, Per Nordlöw wrote:

Right, but that's the case regardless of version(StdUnittest).

On Saturday, 4 September 2021 at 12:31:33 UTC, Dennis wrote:

I don't think so. My guess is that version(StdUnittest) does maximum parsing, maybe only lexing. How can one easily determine if this is the fact? Behaviour of pragma(msg)?

On Saturday, 4 September 2021 at 12:31:33 UTC, Dennis wrote:

Omg. It really seems like it's motivated to do a benchmark with phobos unittests prefixed with

version(StdUnittest)

then. I can make that refactoring in my favorite choice of editor and see the result differ. In terms of binary size, and speed and memory usage of check, build and link time.

On Saturday, 4 September 2021 at 12:40:02 UTC, Per Nordlöw wrote:

Automated that is.

If we want this, shall we format as

version (StdUnittest) [QUALIFIER...] unittest

instead of current

version (StdUnittest)
[QUALIFIER...] unittest

?