Use pytest.raises with match argument in set_subplots tests

Author: nicholas-esterer

Diff for: packages/python/plotly/plotly/tests/test_core/test_graph_objs/test_figure.py

@@ -3,6 +3,7 @@
 import plotly.graph_objects as go
 from plotly.subplots import make_subplots
 from plotly.tests.utils import TestCaseNoTemplate
+import pytest
 
 
 class FigureTest(TestCaseNoTemplate):
@@ -201,24 +202,20 @@ def test_update_overwrite_data(self):
             [{"type": "scatter", "y": [1, 3, 2], "line": {"color": "yellow"}}],
         )
 
-    def test_set_subplots(self):
-        # Test that it works the same as make_subplots for a simple call
-        fig0 = go.Figure()
-        fig0_sp = make_subplots(2, 2)
-        fig0.set_subplots(2, 2)
-        assert fig0.layout == fig0_sp.layout
-        # Test that it accepts the same arguments as make_subplots
-        fig1 = go.Figure()
-        fig1.set_subplots(rows=2, cols=2, horizontal_spacing=0.25, vertical_spacing=0.1)
-        fig1_sp = make_subplots(
-            rows=2, cols=2, horizontal_spacing=0.25, vertical_spacing=0.1
-        )
-        assert fig1.layout == fig1_sp.layout
-        # Test that calling on a figure that already has subplots throws an error.
-        raised = False
-        try:
-            fig1.set_subplots(2, 3)
-        except ValueError as e:
-            assert e.args[0] == "This figure already has subplots."
-            raised = True
-        assert raised
+
+def test_set_subplots():
+    # Test that it works the same as make_subplots for a simple call
+    fig0 = go.Figure()
+    fig0_sp = make_subplots(2, 2)
+    fig0.set_subplots(2, 2)
+    assert fig0.layout == fig0_sp.layout
+    # Test that it accepts the same arguments as make_subplots
+    fig1 = go.Figure()
+    fig1.set_subplots(rows=2, cols=2, horizontal_spacing=0.25, vertical_spacing=0.1)
+    fig1_sp = make_subplots(
+        rows=2, cols=2, horizontal_spacing=0.25, vertical_spacing=0.1
+    )
+    assert fig1.layout == fig1_sp.layout
+    # Test that calling on a figure that already has subplots throws an error.
+    with pytest.raises(ValueError, match=r"^This figure already has subplots\.$"):
+        fig1.set_subplots(2, 3)