Helpful error message

Makefile

@@ -6,7 +6,7 @@ build: typecheck test
 	python -m build
 
 lint:
-	ruff check .
+	ruff check $(LIB)
 
 test:
 	pytest --disable-warnings

modelskill/matching.py

@@ -255,7 +255,10 @@ def match(
             spatial_method=spatial_method,
         )
 
-    assert isinstance(obs, Collection)
+    if isinstance(obs, Collection):
+        assert all(isinstance(o, get_args(ObsInputType)) for o in obs)
+    else:
+        raise TypeError(f"Obs is not the correct type: it is {type(obs)}. Check the order of the arguments (obs, mod).")
 
     if len(obs) > 1 and isinstance(mod, Collection) and len(mod) > 1:
         if not all(isinstance(m, (DfsuModelResult, GridModelResult)) for m in mod):

tests/test_match.py

@@ -542,3 +542,13 @@ def test_compare_model_vs_dummy_for_track(mr1, o3):
 
     # better than dummy 🙂
     assert cmp2.score()["SW_1"] == pytest.approx(0.3524703)
+
+def test_match_obs_model_pos_args_wrong_order_helpful_error_message():
+
+    # match is pretty helpful in converting strings or dataset
+    # so we need to use a ModelResult to trigger the error
+    mr = ms.PointModelResult(data=pd.Series([0.0,0.0], index=pd.date_range("1970", periods=2, freq='d')), name="Zero")
+    obs = ms.PointObservation(data=pd.Series([1.0, 2.0, 3.0], index=pd.date_range("1970", periods=3, freq='h')), name="MyStation")
+
+    with pytest.raises(TypeError, match="order"):
+        ms.match(mr, obs)