Bug: snapshot fails when instantiating InstrumentBase

qcodes/instrument/base.py

@@ -53,6 +53,9 @@ def __init__(self, name: str,
                                          'ChannelList']] = {}
         super().__init__(**kwargs)
 
+        # This is needed for snapshot method to work
+        self._meta_attrs = ['name']
+
     def add_parameter(self, name: str,
                       parameter_class: type=Parameter, **kwargs) -> None:
         """
@@ -396,8 +399,6 @@ def __init__(self, name: str,
         self.add_parameter('IDN', get_cmd=self.get_idn,
                            vals=Anything())
 
-        self._meta_attrs = ['name']
-
         self.record_instance(self)
 
     def get_idn(self) -> Dict[str, Optional[str]]:

qcodes/instrument/channel.py

@@ -35,7 +35,6 @@ def __init__(self, parent: Instrument, name: str, **kwargs) -> None:
 
         self.name = "{}_{}".format(parent.name, str(name))
         self.short_name = str(name)
-        self._meta_attrs = ['name']
 
         self._parent = parent
 
@@ -73,6 +72,7 @@ def name_parts(self) -> List[str]:
         name_parts.append(self.short_name)
         return name_parts
 
+
 class MultiChannelInstrumentParameter(MultiParameter):
     """
     Parameter to get or set multiple channels simultaneously.
@@ -122,6 +122,7 @@ def full_names(self):
 
         return self.names
 
+
 class ChannelList(Metadatable):
     """
     Container for channelized parameters that allows for sweeps over

qcodes/tests/test_instrument.py

@@ -2,7 +2,7 @@
 Test suite for  instument.*
 """
 from unittest import TestCase
-from qcodes.instrument.base import Instrument
+from qcodes.instrument.base import Instrument, InstrumentBase
 from .instrument_mocks import DummyInstrument, MockParabola
 from qcodes.instrument.parameter import Parameter
 import gc
@@ -111,7 +111,33 @@ def test_snapshot_value(self):
 
         snapshot = self.instrument.snapshot()
 
+        self.assertIn('name', snapshot)
+        self.assertEqual('testdummy', snapshot['name'])
+
         self.assertIn('value', snapshot['parameters']['has_snapshot_value'])
         self.assertEqual(42,
                          snapshot['parameters']['has_snapshot_value']['value'])
         self.assertNotIn('value', snapshot['parameters']['no_snapshot_value'])
+
+
+class TestInstrumentBase(TestCase):
+    """
+    This class contains tests that are relevant to the InstrumentBase class.
+    """
+
+    def test_snapshot_and_meta_attrs(self):
+        """Test snapshot of InstrumentBase contains _meta_attrs attributes"""
+        instr = InstrumentBase('instr')
+
+        self.assertEqual(instr.name, 'instr')
+
+        self.assertTrue(hasattr(instr, '_meta_attrs'))
+        self.assertListEqual(instr._meta_attrs, ['name'])
+
+        snapshot = instr.snapshot()
+
+        self.assertIn('name', snapshot)
+        self.assertEqual('instr', snapshot['name'])
+
+        self.assertIn('__class__', snapshot)
+        self.assertIn('InstrumentBase', snapshot['__class__'])