add tests for from_levels_and_cmap (#44)

* add tests for from_levels_and_cmap

* more tests

* add seaborn to list of optional dependencies

Author: mathause

ci/requirements/py37-min-all-deps.yml

@@ -7,6 +7,7 @@ dependencies:
   - cartopy=0.17
   - matplotlib-base=3.4
   - numpy=1.17
+  - seaborn=0.11
   - setuptools=40.4
   - xarray=0.15
 # for testing

docs/installation.md

@@ -9,6 +9,7 @@
 
 ## Optional dependencies
 
+-   [seaborn](https://seaborn.pydata.org/) (0.11 or later)
 -   [xarray](http://xarray.pydata.org/) (0.15 or later)
 
 ## Instructions

mplotutils/tests/test_colormap.py

@@ -0,0 +1,93 @@
+import matplotlib
+import matplotlib.pyplot as plt
+import numpy as np
+import pytest
+
+import mplotutils as mpu
+
+
+def test_from_levels_and_cmap_not_list():
+
+    with pytest.raises(ValueError, match="'levels' must be a list of levels"):
+        mpu.from_levels_and_cmap(3, "Greys")
+
+
+def assert_cmap_norm(cmap, norm, levels, extend):
+
+    zeros = np.zeros(4)
+
+    assert isinstance(cmap, matplotlib.colors.ListedColormap)
+
+    assert cmap.N == len(levels) - 1
+    assert cmap.colorbar_extend == extend
+    np.testing.assert_allclose(cmap.get_bad(), zeros)
+
+    if extend in ("both", "min"):
+        assert np.not_equal(cmap.get_under(), zeros).all()
+    else:
+        assert np.equal(cmap.get_under(), zeros).all()
+
+    if extend in ("both", "max"):
+        assert np.not_equal(cmap.get_over(), zeros).all()
+    else:
+        assert np.equal(cmap.get_over(), zeros).all()
+
+    assert isinstance(norm, matplotlib.colors.BoundaryNorm)
+    np.testing.assert_allclose(norm.boundaries, levels)
+
+
+def test_from_levels_and_cmap():
+
+    levels = [1, 2, 3]
+    extend = "neither"
+    cmap, norm = mpu.from_levels_and_cmap(levels, "viridis", extend=extend)
+    assert_cmap_norm(cmap, norm, levels, extend)
+
+
+@pytest.mark.parametrize("extend", ("neither", "min", "max", "both"))
+def test_from_levels_and_cmap_extend(extend):
+
+    levels = [1, 2, 3]
+    cmap, norm = mpu.from_levels_and_cmap(levels, "viridis", extend=extend)
+    assert_cmap_norm(cmap, norm, levels, extend)
+
+
+def test_from_levels_and_cmap_levels():
+
+    levels = np.arange(-0.35, 0.2, 0.36)
+    cmap, norm = mpu.from_levels_and_cmap(levels, "viridis")
+    assert_cmap_norm(cmap, norm, levels, extend="neither")
+
+
+def test_from_levels_and_cmap_color_list():
+
+    cmap = plt.get_cmap("viridis").colors
+    levels = [1, 2, 3]
+    cmap, norm = mpu.from_levels_and_cmap(levels, cmap)
+    assert_cmap_norm(cmap, norm, levels, extend="neither")
+
+
+def test_from_levels_and_cmap_LinearSegmentedColormap():
+
+    cmap = plt.cm.RdYlGn
+    levels = [1, 2, 3]
+    cmap, norm = mpu.from_levels_and_cmap(levels, cmap)
+    assert_cmap_norm(cmap, norm, levels, extend="neither")
+
+
+def test_from_levels_and_cmap_seaborn_cmap():
+
+    pytest.importorskip("seaborn")
+
+    levels = [1, 2, 3]
+    cmap, norm = mpu.from_levels_and_cmap(levels, "tab10")
+    assert_cmap_norm(cmap, norm, levels, extend="neither")
+
+
+def test_from_levels_and_cmap_colorstring():
+
+    pytest.importorskip("seaborn")
+
+    levels = [1, 2, 3]
+    cmap, norm = mpu.from_levels_and_cmap(levels, "0.1")
+    assert_cmap_norm(cmap, norm, levels, extend="neither")