Add test

rlung · rlung · commit 25e7f73a1110 · 2020-08-01T13:14:11.000-04:00
diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
@@ -660,3 +660,26 @@ def test_quadmesh_set_array():
     coll.set_array(np.ones(9))
     fig.canvas.draw()
     assert np.array_equal(coll.get_array(), np.ones(9))
+
+def test_legend_size_with_inverse_relationship():
+    '''
+    Ensure legend markers scale appropriately when label and size are inversely related.
+    Here label = 5 / size
+    '''
+
+    np.random.seed(19680801)
+    X = np.random.random(50)
+    Y = np.random.random(50)
+    C = 1 - np.random.random(50)
+    S = 5 / C
+
+    leg_sizes = [0.2, 0.4, 0.6, 0.8]
+    fig, ax = plt.subplots()
+    sc = ax.scatter(X, Y, s=S)
+    handles, labels = sc.legend_elements(prop='sizes', num=leg_sizes, func=lambda x: 5 / x)
+
+    # Convert markersize scale to 's' scale
+    handle_sizes = [x.get_markersize() for x in handles]
+    handle_sizes = [5 / x**2 for x in handle_sizes]
+
+    assert_almost_equal(handle_sizes, leg_sizes, decimal=2)
