This issue records @mnatsuhara's excellent idea in https://github.com/microsoft/STL/pull/703#discussion_r436978657 to enhance `tests/std/tests/P0356R5_bind_front/test.cpp`'s coverage after implementing #43 (WG21-P0980 `constexpr` `std::string`).
This issue records Miya Natsuhara (@mnatsuhara)'s excellent idea in #703 (comment) to enhance
tests/std/tests/P0356R5_bind_front/test.cpp's coverage after implementing #43 (WG21-P0980constexprstd::string).