per #2137, enhanced PointStat wrapper to properly set -obs_valid_beg/…

…end command line arguments that fix newly added unit tests

metplus/wrappers/compare_gridded_wrapper.py

@@ -304,12 +304,24 @@ def process_fields(self, time_info):
                                                is_directory=True):
             return
 
+        # set command line arguments
+        self.set_command_line_arguments(time_info)
+
         # set environment variables needed by MET config file
         self.set_environment_variables(time_info)
 
         # run the MET command
         self.build()
 
+    def set_command_line_arguments(self, time_info):
+        """!Set command line arguments in self.args to add to command to run.
+        Nothing is done for CompareGridded wrapper. This function can be
+        overwritten in subclasses.
+
+        @param time_info dictionary with time information
+        """
+        return
+
     def get_command(self):
         """! Builds the command to run the MET application
            @rtype string

metplus/wrappers/point_stat_wrapper.py

@@ -312,7 +312,13 @@ def create_c_dict(self):
 
         return c_dict
 
-    def add_obs_valid_args(self, time_info):
+    def set_command_line_arguments(self, time_info):
+        """!Set command line arguments in self.args to add to command to run.
+        This function is overwritten from CompareGridded wrapper.
+
+        @param time_info dictionary with time information
+        """
+        # set optional obs_valid_beg and obs_valid_end arguments
         for ext in ['BEG', 'END']:
             if self.c_dict[f'OBS_VALID_{ext}']:
                 obs_valid = do_string_sub(self.c_dict[f'OBS_VALID_{ext}'],