Resolve L2SS-247 "2021 07 06 branched from master attribute testing"

Closes L2SS-247

devices/clients/attribute_wrapper.py

 from tango.server import attribute
 from tango import AttrWriteType
-
 import numpy
 
 from devices.device_decorators import only_when_on, fault_on_error
@@ -27,23 +26,24 @@ class attribute_wrapper(attribute):
         """
 
         # ensure the type is a numpy array.
-        # see also https://pytango.readthedocs.io/en/stable/server_api/server.html?highlight=devlong#module-tango.server for 
+        # see also https://pytango.readthedocs.io/en/stable/server_api/server.html?highlight=devlong#module-tango.server for
         # more details about type conversion Python/numpy -> PyTango
         if "numpy" not in str(datatype) and datatype != str:
             raise TypeError("Attribute needs to be a Tango-supported numpy or str type, but has type \"%s\"" % (datatype,))
 
         self.comms_id = comms_id # store data that can be used to identify the comms interface to use. not used by the wrapper itself
         self.comms_annotation = comms_annotation  # store data that can be used by the comms interface. not used by the wrapper itself
-        self.numpy_type = datatype  # tango changes our attribute to their representation (E.g numpy.int64 becomes "DevLong64")
 
         self.init_value = init_value
         is_scalar = dims == (1,)
 
         # tango doesn't recognise numpy.str_, for consistencies sake we convert it here and hide this from the top level
         # NOTE: discuss, idk if this is an important detail somewhere else
-        if datatype is numpy.str_:
+        if datatype is numpy.str_ or datatype is numpy.str:
             datatype = str
 
+        self.numpy_type = datatype  # tango changes our attribute to their representation (E.g numpy.int64 becomes "DevLong64")
+
         # check if not scalar
         if is_scalar:
             # scalar, just set the single dimension.
@@ -131,7 +131,15 @@ class attribute_wrapper(attribute):
         else:
             numpy_dims = dims
 
-        value = numpy.zeros(numpy_dims, dtype=self.numpy_type)
+        if self.dim_x == 1:
+
+            if self.numpy_type == str:
+                value = ''
+            else:
+                value = self.numpy_type(0)
+        else:
+            value = numpy.zeros(numpy_dims, dtype=self.numpy_type)
+
         return value
 
     def set_comm_client(self, client):