fix StringTestCase::FromDouble: newer MSVC versions use three digits for the exponent width

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64470 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/strings/strings.cpp

@@ -758,7 +758,14 @@ void StringTestCase::FromDouble()
     } testData[] =
     {
         { 1.23,             "1.23" },
+        // NB: there are no standards about the minimum exponent width
+        //     and newer MSVC versions use 3 digits as minimum exponent
+        //     width while GNU libc uses 2 digits as minimum width...
+#ifdef __VISUALC__
+        { -3e-10,           "-3e-010" },
+#else
         { -3e-10,           "-3e-10" },
+#endif
         { -0.45678,         "-0.45678" },
     };