feat: add missing contour builder test

Author: PierreRaybaut

plotpy/tests/items/test_contours.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+#
+# Licensed under the terms of the BSD 3-Clause
+# (see plotpy/LICENSE for details)
+
+"""Contour builder test"""
+
+# guitest: show
+
+import numpy as np
+from guidata.qthelpers import qt_app_context
+
+from plotpy.builder import make
+from plotpy.items import ContourItem
+from plotpy.tests import vistools as ptv
+
+
+def create_two_gaussians() -> np.ndarray:
+    """Create two nearby 2D Gaussians with different shapes."""
+    axis = np.linspace(-5.0, 5.0, 300)
+    x, y = np.meshgrid(axis, axis)
+    wide = np.exp(-((x + 0.9) ** 2 + (y + 0.2) ** 2) / (2.0 * 1.2**2))
+    narrow = 0.65 * np.exp(-((x - 1.0) ** 2 + (y - 0.4) ** 2) / (2.0 * 0.6**2))
+    return wide + narrow
+
+
+def test_contours():
+    """Contour plotting on two nearby 2D Gaussians"""
+    with qt_app_context(exec_loop=True):
+        image = create_two_gaussians()
+        contour_items = make.contours(image, np.linspace(0.2, 1.0, 5))
+
+        assert contour_items
+        assert all(isinstance(item, ContourItem) for item in contour_items)
+
+        _win = ptv.show_items(
+            [make.image(image, colormap="cool")] + contour_items,
+            wintitle=test_contours.__doc__,
+            curve_antialiasing=False,
+            lock_aspect_ratio=True,
+        )
+
+
+if __name__ == "__main__":
+    test_contours()