Fix SetRawAnnotations when no stim channel (#838)

* First try to fix

* Add test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

* Whats new

* enforce desired event ids when creating events from annotations

---------

Signed-off-by: Pierre Guetschel <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: PierreGtch

docs/source/whats_new.rst

@@ -45,6 +45,7 @@ Enhancements
 Bugs
 - Fixes the management of include/exclude datasets in :func:`moabb.benchmark`, adds additional verifications (:gh:`834` by `Anton Andreev`_)
 - Fixing pagination issue with figshare (:gh:`839` by `Bruno Aristimunha`_)
+- Fixes :class:`moabb.datasets.preprocessing.SetRawAnnotations` in case no STIM channel is present (:gh:`838` by `Pierre Guetschel`_ and `Simon Kojima`_)
 
 ~~~~
 API changes

moabb/datasets/preprocessing.py

@@ -116,11 +116,20 @@ def transform(self, raw, y=None):
         offset = int(self.interval[0] * raw.info["sfreq"])
         stim_channels = mne.utils._get_stim_channel(None, raw.info, raise_error=False)
         if len(stim_channels) == 0:
-            log.warning(
-                "No stim channel nor annotations found, skipping setting annotations."
+            if raw.annotations is None:
+                log.warning(
+                    "No stim channel nor annotations found, skipping setting annotations."
+                )
+                return raw
+            if not all(isinstance(mrk, int) for mrk in self.event_id.values()):
+                raise ValueError(
+                    "When no stim channel is present, event_id values must be integers (not lists)."
+                )
+            events, _ = mne.events_from_annotations(
+                raw, event_id=self.event_id, verbose=False
             )
-            return raw
-        events = mne.find_events(raw, shortest_event=0, verbose=False)
+        else:
+            events = mne.find_events(raw, shortest_event=0, verbose=False)
         events = _unsafe_pick_events(events, include=_get_event_id_values(self.event_id))
         events[:, 0] += offset
         if len(events) != 0:

moabb/tests/test_paradigms.py

@@ -43,6 +43,24 @@ def used_events(self, dataset):
 
 
 class TestMotorImagery(unittest.TestCase):
+
+    def test_paradigm_interval(self):
+        paradigm = SimpleMotorImagery()
+        for use_annotations in [True, False]:
+            dataset = FakeDataset(
+                paradigm="imagery", annotations=use_annotations, seed=12
+            )
+            dataset.interval = (0, 4)
+            # checking that the random data generation is consistent for the same interval
+            X1, _, _ = paradigm.get_data(dataset, subjects=[1])
+            X2, _, _ = paradigm.get_data(dataset, subjects=[1])
+            np.testing.assert_array_equal(X1, X2)
+
+            dataset.interval = (1, 5)
+            # checking that changing the interval changes the data selected
+            X3, _, _ = paradigm.get_data(dataset, subjects=[1])
+            assert not np.array_equal(X1, X3)
+
     def test_BaseImagery_paradigm(self):
         paradigm = SimpleMotorImagery()
         dataset = FakeDataset(paradigm="imagery")