ENH+RF: inform which unit value is actually overwritten (ignored and set)

Otherwise user is left wondering "what was ignored? it might have been millivolts and now it became volts?" and alike.
While at it I RF code to avoid duplication (evil, tiresome to change) in the touched code

Author: yarikoptic

src/pynwb/icephys.py

@@ -116,10 +116,7 @@ class CurrentClampSeries(PatchClampSeries):
              'default': 'volts'})
     def __init__(self, **kwargs):
         name, data, unit, electrode, gain = popargs('name', 'data', 'unit', 'electrode', 'gain', kwargs)
-        if unit != 'volts':
-            warnings.warn("Unit for %s '%s' is ignored and will be set to 'volts' as per NWB 2.1.0."
-                          % (self.__class__.__name__, name))
-        unit = 'volts'
+        unit = ensure_unit(self, name, unit, 'volts', '2.1.0')
         bias_current, bridge_balance, capacitance_compensation = popargs(
             'bias_current', 'bridge_balance', 'capacitance_compensation', kwargs)
         super().__init__(name, data, unit, electrode, gain, **kwargs)
@@ -170,10 +167,7 @@ class CurrentClampStimulusSeries(PatchClampSeries):
              'default': 'amperes'})
     def __init__(self, **kwargs):
         name, data, unit, electrode, gain = popargs('name', 'data', 'unit', 'electrode', 'gain', kwargs)
-        if unit != 'amperes':
-            warnings.warn("Unit for %s '%s' is ignored and will be set to 'amperes' as per "
-                          "NWB 2.1.0." % (self.__class__.__name__, name))
-        unit = 'amperes'
+        unit = ensure_unit(self, name, unit, 'amperes', '2.1.0')
         super().__init__(name, data, unit, electrode, gain, **kwargs)
 
 
@@ -209,10 +203,7 @@ class VoltageClampSeries(PatchClampSeries):
              'default': 'amperes'})
     def __init__(self, **kwargs):
         name, data, unit, electrode, gain = popargs('name', 'data', 'unit', 'electrode', 'gain', kwargs)
-        if unit != 'amperes':
-            warnings.warn("Unit for %s '%s' is ignored and will be set to 'amperes' as per NWB 2.1.0."
-                          % (self.__class__.__name__, name))
-        unit = 'amperes'
+        unit = ensure_unit(self, name, unit, 'amperes', '2.1.0')
         capacitance_fast, capacitance_slow, resistance_comp_bandwidth, resistance_comp_correction, \
             resistance_comp_prediction, whole_cell_capacitance_comp, whole_cell_series_resistance_comp = popargs(
                 'capacitance_fast', 'capacitance_slow', 'resistance_comp_bandwidth',
@@ -245,10 +236,7 @@ class VoltageClampStimulusSeries(PatchClampSeries):
              'default': 'volts'})
     def __init__(self, **kwargs):
         name, data, unit, electrode, gain = popargs('name', 'data', 'unit', 'electrode', 'gain', kwargs)
-        if unit != 'volts':
-            warnings.warn("Unit for %s '%s' is ignored and will be set to 'volts' as per "
-                          "NWB 2.1.0." % (self.__class__.__name__, name))
-        unit = 'volts'
+        unit = ensure_unit(self, name, unit, 'volts', '2.1.0')
         super().__init__(name, data, unit, electrode, gain, **kwargs)
 
 
@@ -309,3 +297,17 @@ def __get_row_ids(self, sweep_number):
         """
 
         return [index for index, elem in enumerate(self['sweep_number'].data) if elem == sweep_number]
+
+
+def ensure_unit(self, name, current_unit, unit, nwb_version):
+    """A helper to ensure correct unit used.
+
+    Issues a warning with details if `current_unit` is to be ignored, and
+    `unit` to be used instead.
+    """
+    if current_unit != unit:
+        warnings.warn(
+            "Unit '%s' for %s '%s' is ignored and will be set to '%s' "
+            "as per NWB %s."
+            % (current_unit, self.__class__.__name__, name, unit, nwb_version))
+    return unit

tests/unit/test_icephys.py

@@ -205,7 +205,7 @@ def test_init(self):
     def test_unit_warning(self):
         electrode_name = GetElectrode()
 
-        msg = "Unit for CurrentClampSeries 'test_cCS' is ignored and will be set to 'volts' as per NWB 2.1.0."
+        msg = "Unit 'unit' for CurrentClampSeries 'test_cCS' is ignored and will be set to 'volts' as per NWB 2.1.0."
         with self.assertWarnsWith(UserWarning, msg):
             cCS = CurrentClampSeries('test_cCS', list(), electrode_name, 1.0, "stimset", 2.0, 3.0, 4.0,
                                      timestamps=list(), unit='unit')
@@ -229,7 +229,7 @@ def test_init(self):
     def test_unit_warning(self):
         electrode_name = GetElectrode()
 
-        msg = "Unit for IZeroClampSeries 'test_iZCS' is ignored and will be set to 'volts' as per NWB 2.1.0."
+        msg = "Unit 'unit' for IZeroClampSeries 'test_iZCS' is ignored and will be set to 'volts' as per NWB 2.1.0."
         with self.assertWarnsWith(UserWarning, msg):
             iZCS = IZeroClampSeries('test_iZCS', list(), electrode_name, 1.0, timestamps=list(), unit='unit')
         self.assertEqual(iZCS.unit, 'volts')
@@ -249,7 +249,7 @@ def test_init(self):
     def test_unit_warning(self):
         electrode_name = GetElectrode()
 
-        msg = ("Unit for CurrentClampStimulusSeries 'test_cCSS' is ignored and will be set to 'amperes' as per NWB "
+        msg = ("Unit 'unit' for CurrentClampStimulusSeries 'test_cCSS' is ignored and will be set to 'amperes' as per NWB "
                "2.1.0.")
         with self.assertWarnsWith(UserWarning, msg):
             cCSS = CurrentClampStimulusSeries('test_cCSS', list(), electrode_name, 1.0, timestamps=list(), unit='unit')
@@ -279,7 +279,7 @@ def test_init(self):
     def test_unit_warning(self):
         electrode_name = GetElectrode()
 
-        msg = "Unit for VoltageClampSeries 'test_vCS' is ignored and will be set to 'amperes' as per NWB 2.1.0."
+        msg = "Unit 'unit' for VoltageClampSeries 'test_vCS' is ignored and will be set to 'amperes' as per NWB 2.1.0."
         with self.assertWarnsWith(UserWarning, msg):
             vCS = VoltageClampSeries('test_vCS', list(), electrode_name,
                                      1.0, "stimset", 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, timestamps=list(), unit='unit')
@@ -299,7 +299,7 @@ def test_init(self):
     def test_unit_warning(self):
         electrode_name = GetElectrode()
 
-        msg = "Unit for VoltageClampStimulusSeries 'test_vCSS' is ignored and will be set to 'volts' as per NWB 2.1.0."
+        msg = "Unit 'unit' for VoltageClampStimulusSeries 'test_vCSS' is ignored and will be set to 'volts' as per NWB 2.1.0."
         with self.assertWarnsWith(UserWarning, msg):
             vCSS = VoltageClampStimulusSeries('test_vCSS', list(), electrode_name, 1.0, timestamps=list(), unit='unit')
         self.assertEqual(vCSS.unit, 'volts')