improve error msg for plot coilis

PlasmaControl · Aug 16, 2024 · e39d08f · e39d08f
1 parent 2646876
commit e39d08f
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Showing 2 changed files with 10 additions and 0 deletions.
diff --git a/desc/plotting.py b/desc/plotting.py
@@ -2384,6 +2384,8 @@ def plot_coils(coils, grid=None, fig=None, return_data=False, **kwargs):
         dictionary of the data plotted, only returned if ``return_data=True``
 
     """
+    from desc.coils import _Coil
+
     lw = kwargs.pop("lw", 5)
     ls = kwargs.pop("ls", "solid")
     figsize = kwargs.pop("figsize", (10, 10))
@@ -2394,6 +2396,12 @@ def plot_coils(coils, grid=None, fig=None, return_data=False, **kwargs):
         ValueError,
         f"plot_coils got unexpected keyword argument: {kwargs.keys()}",
     )
+    errorif(
+        not isinstance(coils, _Coil),
+        ValueError,
+        "Expected `coils` to be object of type `_Coil`, instead got type"
+        f" {type(coils)}",
+    )
 
     if not isinstance(lw, (list, tuple)):
         lw = [lw]

diff --git a/tests/test_plotting.py b/tests/test_plotting.py
@@ -801,6 +801,8 @@ def test_plot_coils():
     coil.rotate(angle=np.pi / N)
     coils = CoilSet.linspaced_angular(coil, I, [0, 0, 1], np.pi / NFP, N // NFP // 2)
     coils2 = MixedCoilSet.from_symmetry(coils, NFP, True)
+    with pytest.raises(ValueError, match="Expected `coils`"):
+        plot_coils("not a coil")
     fig, data = plot_coils(coils2, return_data=True)
 
     def flatten_coils(coilset):