Resolve L2SS-363 "01 12 2021 get rw values from hardware"

Changed RW caching to instead get the value from hardware.

Fixed bug in our unit tests that caused the scalar_R tests to read RW values instead of R values

Closes L2SS-363

tangostationcontrol/tangostationcontrol/clients/attribute_wrapper.py

@@ -70,47 +70,32 @@ class attribute_wrapper(attribute):
                 max_dim_y = 0
 
         if access == AttrWriteType.READ_WRITE:
-            """ if the attribute is of READ_WRITE type, assign the RW and write function to it"""
+            """ if the attribute is of READ_WRITE type, assign the write function to it"""
 
             @only_in_states([DevState.STANDBY, DevState.ON], log=False)
             @fault_on_error()
-            def read_RW(device):
-                # print("read_RW {}, {}x{}, {}, {}".format(me.name, me.dim_x, me.dim_y, me.attr_type, me.value))
+            def write_func_wrapper(device, value):
                 """
-                read_RW returns the value that was last written to the attribute
-                """
-                try:
-                    return device.value_dict[self]
-                except Exception as e:
-                    raise Exception(f"Attribute read_RW function error, attempted to read value_dict with key: `{self}`, are you sure this exists?") from e
-
-            @only_in_states([DevState.STANDBY, DevState.ON], log=False)
-            @fault_on_error()
-            def write_RW(device, value):
-                """
-                _write_RW writes a value to this attribute
+                write_func_wrapper writes a value to this attribute
                 """
 
                 self.write_function(value)
-                device.value_dict[self] = value
 
-            self.fget = read_RW
-            self.fset = write_RW
+            self.fset = write_func_wrapper
 
 
-        else:
-            """ if the attribute is of READ type, assign the read function to it"""
+        """ Assign the read function to the attribute"""
 
-            @only_in_states([DevState.STANDBY, DevState.ON], log=False)
-            @fault_on_error()
-            def read_R(device):
-                """
-                _read_R reads the attribute value, stores it and returns it"
-                """
-                device.value_dict[self] = self.read_function()
-                return device.value_dict[self]
+        @only_in_states([DevState.STANDBY, DevState.ON], log=False)
+        @fault_on_error()
+        def read_func_wrapper(device):
+            """
+            read_func_wrapper reads the attribute value, stores it and returns it"
+            """
+            device.value_dict[self] = self.read_function()
+            return device.value_dict[self]
 
-            self.fget = read_R
+        self.fget = read_func_wrapper
 
         super().__init__(dtype=datatype, max_dim_y=max_dim_y, max_dim_x=max_dim_x, access=access, **kwargs)