fix parameter inheritance

Correct inheritance has to follow the MRO, not only consider
the direct base classes.

Patchset 3: changed only tests, indicating that we need to change the code

Following patchsets include a major change in params.py and
modules.py. The parameter properties for inheritance, corresponding
mainly to the constructor arguments have to be stored separately
from the property values including inherited stuff.

Change-Id: Ibcbccb6abcc22e7e2d91df8f70ef64226684d8cc
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/26805
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>

secop/datatypes.py

@@ -958,7 +958,7 @@ class CommandType(DataType):
         argstr = repr(self.argument) if self.argument else ''
         if self.result is None:
             return 'CommandType(%s)' % argstr
-        return 'CommandType(%s)->%s' % (argstr, repr(self.result))
+        return 'CommandType(%s, %s)' % (argstr, repr(self.result))
 
     def __call__(self, value):
         """return the validated argument value or raise"""
@@ -999,7 +999,10 @@ class DataTypeType(DataType):
         returns the value or raises an appropriate exception"""
         if isinstance(value, DataType):
             return value
-        raise ProgrammingError('%r should be a DataType!' % value)
+        try:
+            return get_datatype(value)
+        except Exception as e:
+            raise ProgrammingError(e) from None
 
     def export_value(self, value):
         """if needed, reformat value for transport"""
@@ -1034,6 +1037,13 @@ class ValueType(DataType):
         """
         raise NotImplementedError
 
+    def setProperty(self, key, value):
+        """silently ignored
+
+        as ValueType is used for the datatype default, this makes code
+        shorter for cases, where the datatype may not yet be defined
+        """
+
 
 class NoneOr(DataType):
     """validates a None or smth. else"""