tdf#40517 Unit test for question marks in number format

Unit test for https://gerrit.libreoffice.org/21021/

Add unit test for Engineering format
Add unit test for optional sign in exponent

Change-Id: I958ccdcc68a4e496cbd4bdc74d0650c133f3a3f7
Reviewed-on: https://gerrit.libreoffice.org/21824
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

basic/qa/vba_tests/format.vb

@@ -348,6 +348,10 @@ Sub Custom_Number_Format_Sample()
     TestLog_ASSERT TestStr = ".25%", "##.###\%: " & TestStr
     'MsgBox TestStr
 
+    TestStr = Format(12.25, "0.???") '12.25_
+    TestLog_ASSERT TestStr = "12.25 ", "0.???: " & TestStr
+    'MsgBox TestStr
+
     Exit Sub
 errorHandler:
         TestLog_ASSERT (false), testName & ": hit error handler"

sc/qa/unit/data/contentCSV/numberFormat.csv

@@ -5,3 +5,5 @@
 25 31/82
 FALSE,TRUE
 />
+258.9E3,-953E-06
+0.5