Enable Unicode support by default

test/CMakeLists.txt

@@ -146,6 +146,9 @@ if (NOT MSVC_STATIC_RUNTIME)
   if (FMT_PEDANTIC)
     target_compile_options(posix-mock-test PRIVATE ${PEDANTIC_COMPILE_FLAGS})
   endif ()
+  if (MSVC)
+    target_compile_options(posix-mock-test PRIVATE /utf-8)
+  endif ()
   add_test(NAME posix-mock-test COMMAND posix-mock-test)
   add_fmt_test(os-test)
 endif ()