small set of tests for CenteredNorm

jpmattern · jpmattern · commit 58d605735891 · 2020-10-02T07:43:08.000-07:00
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
@@ -359,6 +359,27 @@ def test_BoundaryNorm():
     assert_array_equal(cmshould(mynorm(x)), cmref(refnorm(x)))
 
 
+def test_CenteredNorm():
+    # Assert equivalence to symmetrical Normalize.
+    x = np.random.normal(size=100)
+    x_maxabs = np.max(np.abs(x))
+    norm_ref = mcolors.Normalize(vmin=-x_maxabs, vmax=x_maxabs)
+    norm = mcolors.CenteredNorm()
+    assert_array_almost_equal(norm_ref(x), norm(x))
+    # Check that vcenter is in the center of vmin and vmax
+    # when vcenter is set.
+    vcenter = int(np.random.normal(scale=50))
+    norm = mcolors.CenteredNorm(vcenter=vcenter)
+    norm.autoscale_None([1, 2])
+    assert norm.vmax + norm.vmin == 2 * vcenter
+    # Check that halfrange input works correctly.
+    x = np.random.normal(size=10)
+    norm = mcolors.CenteredNorm(vcenter=0.5, halfrange=0.5)
+    assert_array_almost_equal(x, norm(x))
+    norm = mcolors.CenteredNorm(vcenter=1, halfrange=1)
+    assert_array_almost_equal(x, 2 * norm(x))
+
+
 @pytest.mark.parametrize("vmin,vmax", [[-1, 2], [3, 1]])
 def test_lognorm_invalid(vmin, vmax):
     # Check that invalid limits in LogNorm error
