[libcxx] [test] Clarify and improve consistency in lexically_relative_and_proximate.pass.cpp. NFC.

[mstorsjo]

Summary

Use "expect" instead of "output" for generating "proximate_expected".
pass the arguments to PathEq in the same order as above.

[curdeius]

LGTM.

[• Quuxplusone]

libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp

87–89

Please name the variable proximate_expect instead of proximate_expected; or else name the variable and field above expected instead of expect. But they should be consistent with each other, one way or another.

I had suggested using expect.empty() instead of expect.native().empty(), on the assumption that they do the same thing. I just checked the code in <filesystem> to be sure, and yeah, it sure looks like they do the same thing. Can you think of any reason the original programmer might have used expect.native().empty() here instead of the more natural expect.empty()?

[mstorsjo]

libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp

87–89

I can't see a good reason not to just use path::empty(), changing to use that. And renaming the variable.

[mstorsjo]

Renamed the variable, using .empty() instead of .native().empty()

libcxx/test/std/input.output/filesystems/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp

auto ReportErr = [&](const char* Testing, fs::path const& Output,
         Expected.string().c_str(), Output.string().c_str());
     };
     if (!PathEq(output, expect))
       ReportErr("path::lexically_relative", output, expect);
     const fs::path proximate_output = p.lexically_proximate(TC.base);
     // [path.gen] lexically_proximate
     // Returns: If the value of lexically_relative(base) is not an empty path,
     // return it. Otherwise return *this.
-    const fs::path proximate_expected = output.native().empty() ? p
-        : output;
-    if (!PathEq(proximate_expected, proximate_output))
-      ReportErr("path::lexically_proximate", proximate_output, proximate_expected);
+    const fs::path proximate_expect = expect.empty() ? p : expect;
+    if (!PathEq(proximate_output, proximate_expect))
+      ReportErr("path::lexically_proximate", proximate_output, proximate_expect);
   }
   return Failed;
 }