TST: add test for refactored trajectory guard code

test/test_pysindy.py

@@ -22,6 +22,7 @@
 from sklearn.model_selection import TimeSeriesSplit
 from sklearn.utils.validation import check_is_fitted
 
+from pysindy import pysindy
 from pysindy import SINDy
 from pysindy.differentiation import SINDyDerivative
 from pysindy.differentiation import SmoothedFiniteDifference
@@ -436,6 +437,14 @@ def test_score_discrete_time(data_discrete_time):
     assert model.score(x, x_dot=x) < 1
 
 
+def test_bad_multiple_trajectories(data_multiple_trajectories):
+    x, t = data_multiple_trajectories
+    with pytest.raises(TypeError):
+        pysindy._check_multiple_trajectories(x, x_dot=x[0], u=None)
+    with pytest.raises(ValueError):
+        pysindy._check_multiple_trajectories(x, x_dot=x[:-1], u=None)
+
+
 def test_fit_discrete_time_multiple_trajectories(
     data_discrete_time_multiple_trajectories,
 ):