Improve error when settings timestamps (#377)

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 ### Improvements
 * Removed unnecessary import checks for scipy, h5py, and zarr [PR #364](https://github.com/catalystneuro/roiextractors/pull/364)
+* Improved the error message for the `set_timestamps` method in the `ImagingExtractor` class[PR #377](https://github.com/catalystneuro/roiextractors/pull/377)
 
 ### Testing
 

src/roiextractors/imagingextractor.py

@@ -192,10 +192,24 @@ def set_times(self, times: ArrayType) -> None:
         Parameters
         ----------
         times: array-like
-            The times in seconds for each frame
+            The times in seconds for each frame.
+
+        Raises
+        ------
+        ValueError
+            If the length of 'times' does not match the number of frames.
         """
-        assert len(times) == self.get_num_frames(), "'times' should have the same length of the number of frames!"
-        self._times = np.array(times).astype("float64")
+        num_frames = self.get_num_frames()
+        num_timestamps = len(times)
+
+        if num_timestamps != num_frames:
+            raise ValueError(
+                f"Mismatch between the number of frames and timestamps: "
+                f"{num_frames} frames, but {num_timestamps} timestamps provided. "
+                "Ensure the length of 'times' matches the number of frames."
+            )
+
+        self._times = np.array(times).astype("float64", copy=False)
 
     def has_time_vector(self) -> bool:
         """Detect if the ImagingExtractor has a time vector set or not.

tests/test_internals/test_multiimagingextractor.py

@@ -116,11 +116,13 @@ def test_get_video_single_frame(self):
         assert_array_equal(test_frames, expected_frames)
 
     def test_set_incorrect_times(self):
-        with self.assertRaisesWith(
-            exc_type=AssertionError,
-            exc_msg="'times' should have the same length of the number of frames!",
-        ):
+        with self.assertRaises(ValueError) as cm:
             self.multi_imaging_extractor.set_times(times=np.arange(0, 10) / 30.0)
+        self.assertEqual(
+            str(cm.exception),
+            "Mismatch between the number of frames and timestamps: 30 frames, but 10 timestamps provided. "
+            "Ensure the length of 'times' matches the number of frames.",
+        )
 
         self.assertEqual(self.multi_imaging_extractor._times, None)