Use plt.subplots for safety.

And no longer need copy.deepcopy.

Author: samcunliffe

Diff for: src/napari_matplotlib/tests/test_theme.py

@@ -1,5 +1,3 @@
-from copy import deepcopy
-
 import napari
 import numpy as np
 import pytest
@@ -110,11 +108,13 @@ def test_no_theme_side_effects(make_napari_viewer):
 
     # some plotting unrelated to napari-matplotlib
     image = np.random.random((3, 3))
-    plt.imshow(image)
-    plt.xlabel("something unrelated to napari (x)")
-    plt.ylabel("something unrelated to napari (y)")
-    plt.title("this plot style should not change with napari styles or themes")
-    plt.tight_layout()
-    unrelated_figure = plt.gcf()
-
-    return deepcopy(unrelated_figure)
+    unrelated_figure, ax = plt.subplots()
+    ax.imshow(image)
+    ax.set_xlabel("something unrelated to napari (x)")
+    ax.set_ylabel("something unrelated to napari (y)")
+    ax.set_title(
+        "this plot style should not change with napari styles or themes"
+    )
+    unrelated_figure.tight_layout()
+
+    return unrelated_figure