bette error message and docstring to test

Author: h-mayorquin

src/spikeinterface/core/channelslice.py

@@ -31,8 +31,11 @@ def __init__(self, parent_recording, channel_ids=None, renamed_channel_ids=None)
         parents_chan_ids = parent_recording.get_channel_ids()
 
         # some checks
-        is_channel_in_parent = [chan_id in parents_chan_ids.tolist() for chan_id in self._channel_ids.tolist()]
-        assert all(is_channel_in_parent), "ChannelSliceRecording : channel ids are not all in parents"
+        # We use lists to compare numpy scalar types as their python versions (e.g. int vs int64())
+        channel_ids_not_in_parents = [id for id in self._channel_ids.tolist() if id not in parents_chan_ids.tolist()]
+        assert (
+            len(channel_ids_not_in_parents) == 0
+        ), f"ChannelSliceRecording : channel ids {channel_ids_not_in_parents} are not all in parent ids {parents_chan_ids}"
 
         assert len(self._channel_ids) == len(
             self._renamed_channel_ids
@@ -42,6 +45,7 @@ def __init__(self, parent_recording, channel_ids=None, renamed_channel_ids=None)
         ), "ChannelSliceRecording : channel_ids are not unique"
 
         sampling_frequency = parent_recording.get_sampling_frequency()
+        assert sampling_frequency > 0, "Sampling frequency must be positive."
 
         BaseRecording.__init__(
             self,

src/spikeinterface/core/tests/test_channelsaggregationrecording.py

@@ -119,6 +119,12 @@ def test_channel_aggregation_does_not_preserve_ids_not_the_same_type():
 
 
 def test_channel_aggregation_with_string_dtypes_of_different_size():
+    """
+    Fixes issue https://github.com/SpikeInterface/spikeinterface/issues/3733
+
+    This tests that the channel ids are propagated in the aggregation even if they are strings of different
+    string dtype sizes.
+    """
     recording1 = generate_recording(num_channels=2, durations=[10], set_probe=False)
     recording1 = recording1.rename_channels(new_channel_ids=np.array(["8", "9"], dtype="<U1"))