MNT: install contextily with the other optional requirements

requirements-optional.txt

@@ -7,5 +7,6 @@ imageio
 multiprocess>=0.70
 statsmodels
 prettytable
+contextily>=1.0.0; python_version < '3.14'
 pyvista>=0.45
 imageio-ffmpeg>=0.5

tests/unit/simulation/test_monte_carlo_plots_background.py

@@ -1,4 +1,5 @@
 # pylint: disable=unused-argument,assignment-from-no-return
+import math
 import os
 import urllib.error
 from unittest.mock import MagicMock, patch
@@ -19,6 +20,33 @@
 )
 
 
+@pytest.fixture(autouse=True)
+def mock_background_tiles(monkeypatch):
+    """Return deterministic map tiles without contacting a tile provider."""
+    contextily = import_optional_dependency("contextily")
+
+    def mock_bounds2img(west, south, east, north, **kwargs):
+        earth_radius = 6378137.0
+
+        def to_mercator(longitude, latitude):
+            x = earth_radius * math.radians(longitude)
+            y = earth_radius * math.log(
+                math.tan(math.pi / 4 + math.radians(latitude) / 2)
+            )
+            return x, y
+
+        min_x, min_y = to_mercator(west, south)
+        max_x, max_y = to_mercator(east, north)
+        return np.zeros((2, 2, 3), dtype=np.uint8), (
+            min_x,
+            max_x,
+            min_y,
+            max_y,
+        )
+
+    monkeypatch.setattr(contextily, "bounds2img", mock_bounds2img)
+
+
 class MockMonteCarlo(MonteCarlo):
     """Create a mock class to test the method without running a real simulation.