libtime [WP]: add a test function for norm bug

src/libs/libtime/tests/testlibtime.f

@@ -362,6 +362,8 @@ c
       print *,string
       endif
 
+      call normbugtest
+
       stop
    99 stop 'ERROR: opening file'
    98 stop 'ERROR: reading from file'
@@ -478,3 +480,29 @@ c----------------------------------------------------------------------
    50 format('year ',i4,' is a leap year')
    51 format('year ',i4,' is no leap year')
       end
+c ----------------------------------------------------------------------
+      subroutine normbugtest()
+c
+c test bug of norm-subroutine found in 11/2017
+c if seconds are integer multiples of -60 or hours are integer multiples
+c of -24 or similar, the norm function does not provide the desired
+c output
+c
+      integer date1(7), date2(7), date3(7)
+      character string*40
+c
+
+      print *,'isolate'
+      call time_clear(date1)
+      date1(1)=2018
+      date1(2)=13   
+      date1(3)=-23
+      date1(4)=0
+      call time_util_warning_report_time('norm bug test',date1)
+      call time_norm(date1)
+      call time_util_warning_report_time('norm bug test',date1)
+      call time_norm(date1)
+      call time_util_warning_report_time('norm bug test',date1)
+      return
+      end
+