add len check for all position elements

src/pynwb/ecephys.py

@@ -41,8 +41,7 @@ def __init__(self, **kwargs):
                     position_dtype_valid = False
             if position_dtype_valid:  # If we have list of element, then check that the elements are of length 3
                 try:
-                    if len(args_to_set['position'][0]) != 3:
-                        position_dtype_valid = False
+                    position_dtype_valid = all([len(pos) == 3 for pos in args_to_set['position']])
                 except TypeError:  # len not supported by first_position
                     position_dtype_valid = False
             if not position_dtype_valid:

tests/unit/test_ecephys.py

@@ -223,6 +223,12 @@ def test_init_position_bad(self):
                            location='electrode location',
                            device=dev1,
                            position=np.array([(1., 2.)], dtype=np.dtype([('x', float), ('y', float)])))
+        with self.assertRaises(ValueError):
+            ElectrodeGroup(name='elec1',
+                           description='electrode description',
+                           location='electrode location',
+                           device=dev1,
+                           position=[(1, 2, 3), (4, 5)])
 
 
 class EventDetectionConstructor(TestCase):