tdf#102507 Add qa test of left aligned denominator

New behavior of format # ?/??? gives for 3.5
3 1/2
instead of
3 1/  2

Change-Id: I87f4a71fb13d8424017d557213bb4d279de28af5
Reviewed-on: https://gerrit.libreoffice.org/30167Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>

svl/qa/unit/svl.cxx

@@ -1178,6 +1178,11 @@ void Test::testUserDefinedNumberFormats()
         sExpected = "-575 540/697";
         checkPreviewString(aFormatter, sCode, -575.774749601315, eLang, sExpected);
     }
+    {  // tdf#102507: left alignment of denominator
+        sCode = "# ?/???";
+        sExpected = "3 1/2  ";
+        checkPreviewString(aFormatter, sCode, 3.5, eLang, sExpected);
+    }
     {  // tdf#100594: forced denominator
         sCode = "# ?/100";
         sExpected = " 6/100";