@miscco Could we trouble you to add tests for these things now that we have tests in the repo?

yes thats on my list for the coming days

Lets write some tests...

:: cries in tuple ::

On a more serious note I dont think I can write the tests fo the *_inserter as we do not have constexpr containers with push_back

:: cries in tuple ::

Yeah, that's the thing with this change and why we aren't already shipping it. A few lines of product code but a lot of tests are necessary. (That's why we haven't jumped on / tried to merge this now that we have tests here on GH)

On a more serious note I dont think I can write the tests fo the *_inserter as we do not have constexpr containers with push_back

You can write something like this pseudocode:

struct constexpr_container {
    using value_type = int;

    array<5> buffer{};
    size_t selected = 0;
    void push_back(int i) { buffer[selected++] = i; }
};

constexpr bool test() {
    constexpr_container c;
    auto tested = back_inserter(c);
    *tested++ = 42;
    *tested++ = 1729;
    *tested++ = 1234;
    assert(c.buffer == {42, 1729, 1234, 0, 0});
    return true;
}

int main() {
assert(test());
static_assert(test());
}

@BillyONeal Thanks a lot for the code example. I will try it out, the other tests are hopefully finished. I went with all those tuple constructors on cppreference

I went through all the changes and even found some bugs.

Who would have thought that tests do actually help.

And people wonder why I'm so adamant about "no product changes without corresponding tests"

Do you have no faith?

I am a random person from the internet, what could go wrong?

None.

I am a random person from the internet, what could go wrong?

It has nothing to do with you being a random person on the internet, only the "person" part. The only person I've seen with a brain compiler with a near 0% failure rate is Stephan ... and even then not close enough to 0 that I don't want tests :)

I rebased on #589

Rebased again due to whatever conflict there was

From #599 (comment): we'll need to rebase this atop #599, update the value of __cpp_lib_array_constexpr, and fix libc++'s language.support\support.limits\support.limits.general\array.version.pass.cpp test.

So I rebased upon @Weheineman work and now I get some erros that I really do not understand:

--
C:\agent_work\1\s\tests\std\tests\Dev11_0343056_pair_tuple_ctor_sfinae\test.cpp(150,19): error: unused variable 't3' [-Werror,-Wunused-variable]

    tuple<A*> t3(allocator_arg, al, nullptr);
              ^

C:\agent_work\1\s\tests\std\tests\Dev11_0343056_pair_tuple_ctor_sfinae\test.cpp(144,19): error: unused variable 't1' [-Werror,-Wunused-variable]

    tuple<A*> t1(allocator_arg, al);
              ^

2 errors generated.

Those variables were unused before. How does my change affect this code?

The other errors seem valid as string_view::copy was incorrectly marked as constexpr in C++17 and I will simply add a #if _HAS_CXX20

Rebased on master. I still have no Idea why the tests a suddenly failing.

Should we investigate or should we simply add a (void) to supress those warnings

I believe the product code is done - just need to review the test and extend it for overlapping ranges.

That isa simple and elegant solution to the mess I did with those char_traits. Thanks a lot 👍

Summary of test changes:

• Unwrap comment.
• Rename first and second tuples to avoid not-really-shadowing meow.first and meow.second.
• In general, attempt to use unique values for test data, so corresponding values are easier to see.
• Add asserts to verify that operations work correctly, in addition to compiling.
• Style: Use {} to initialize pair even though it performs value-initialization.
• Style: Use copyAssignment as the assignment source for copyAssignmentConvertible.
• Change comment to test pair swap because both member and non-member swap are being tested. Ditto test array swap.
• Don't test internal _Alloc_exact_args_t machinery.
• Test more empty tuple<> operations: allocator move-construction, copy assignment, and move assignment.
• Test more tuple operations:
  • The const Types&... constructor is rarely used, but it's mainly used for things that don't perfectly forward, like braces and 0 as a null pointer constant. Added tuple_alloc_non_forwarding_value to test this.
  • We need to move(conversionInput) and move(conversionInputPair), otherwise they'll be copied. (Note: it's okay to "reuse" moved-from objects here, since they're ultimately storing int and double etc. where moves don't actually modify them.)
  • Assignments.
• Test empty array::fill.
• The insert iterator tests are usually using non-const rvalues like 42, so we actually need an lvalue (or here, a const lvalue) to test the copy overload. So, change move(toBeMoved) to toBeCopied.
• Add comprehensive tests for char_traits move/copy/assign and basic_string_view::copy. This covers the 5 character types: char, char16_t, char32_t, wchar_t, and char8_t. I chose to replicate the code instead of macroizing the literals.

Stephan: This is good, just some final touches.

Also Stephan: Add a zillion lines of test, fixes bad style, cleanes up everything.

You are amazing.

And terryfing

But mostly amazing

/azp run

One more change - I requested compiler support from MSVC (DevCom-1046483) and EDG (Microsoft-internal VSO-1129974), so I added a centralized macro that we'll be able to update in the future, with a TRANSITION comment citing the bug numbers.

Thanks for building one more stage of the C++20 rocket! 🚀 😸