add function to get warnlog unit number and try to fix ci fails

mpp/include/mpp_util.inc

@@ -136,6 +136,19 @@
   end if
   end subroutine mpp_init_warninglog
 
+  !> @brief This function returns unit number for the warning log
+  !! if on the root pe, otherwise returns the etc_unit value (usually /dev/null)
+  function warnlog()
+    integer :: warnlog
+    if(.not. module_is_initialized) call mpp_error(FATAL, "mpp_mod: warnlog cannot be called before mpp_init") 
+    if(root_pe .eq. pe) then
+      warnlog = warn_unit
+    else
+      warnlog = etc_unit
+    endif
+    return
+  end function warnlog 
+
   !#####################################################################
   subroutine mpp_set_warn_level(flag)
     integer, intent(in) :: flag

mpp/mpp.F90

@@ -202,7 +202,7 @@ module mpp_mod
   public :: mpp_init_test_read_namelist, mpp_init_test_etc_unit, mpp_init_test_requests_allocated
 
   !--- public interface from mpp_util.h ------------------------------
-  public :: stdin, stdout, stderr, stdlog, lowercase, uppercase, mpp_error, mpp_error_state
+  public :: stdin, stdout, stderr, stdlog, warnlog, lowercase, uppercase, mpp_error, mpp_error_state
   public :: mpp_set_warn_level, mpp_sync, mpp_sync_self, mpp_pe
   public :: mpp_npes, mpp_root_pe, mpp_set_root_pe, mpp_declare_pelist
   public :: mpp_get_current_pelist, mpp_set_current_pelist, mpp_get_current_pelist_name

test_fms/mpp/test_stdlog.sh

@@ -43,6 +43,10 @@ sed -i 's/1/2/' input.nml
 test_expect_failure "test stdlog and stdwarn with fatal output" '
     mpirun -n 2 ../test_stdlog
 '
+# sync the filesystem and sleep for a sec so the slower systems(CI)
+# can mv and read the output from the previous test
+sync
+sleep 1
 # move file so we don't overwrite
 mv warnfile.000000.out warnfile.000000.out.old
 sed -i 's/2/3/' input.nml