Fix drawing warning (#512)

* Fix drawing warning

* added unit tests

* fix test error

Using pytest best practices (https://docs.pytest.org/en/7.0.x/how-to/capture-warnings.html#additional-use-cases-of-warnings-in-tests)

tests/drawing/test_draw.py

@@ -1,3 +1,5 @@
+import warnings
+
 import matplotlib.pyplot as plt
 import numpy as np
 import pytest
@@ -514,7 +516,7 @@ def test_draw_multilayer(edgelist8):
     # node_size
     assert np.all(node_coll4.get_sizes() == np.array([10**2]))
 
-    plt.close()
+    plt.close("all")
 
 
 def test_draw_dihypergraph(diedgelist2, edgelist8):
@@ -587,16 +589,14 @@ def test_draw_dihypergraph(diedgelist2, edgelist8):
     for patch in ax1.patches:  # lines
         assert patch.get_zorder() == 0
 
-    plt.close("all")
-
     # test toggle for edges
     fig, ax2 = plt.subplots()
     ax2, collections = xgi.draw_dihypergraph(DH, edge_marker_toggle=False, ax=ax2)
     node_coll, phantom_node_coll = collections
     assert len(ax2.collections) == 1
     assert phantom_node_coll is None
 
-    plt.close()
+    plt.close("all")
 
     # test XGI ERROR raise
     with pytest.raises(XGIError):
@@ -622,3 +622,20 @@ def test_draw_dihypergraph_with_str_labels_and_isolated_nodes():
     assert len(node_coll4.get_offsets()) == 6  # number of original nodes
     assert len(phantom_node_coll4.get_offsets()) == 2  # number of original edges
     assert len(ax4.patches) == 7  # number of lines
+    plt.close()
+
+
+def test_issue_499(edgelist8):
+    H = xgi.Hypergraph(edgelist8)
+
+    fig, ax = plt.subplots()
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        ax, collections = xgi.draw(H, ax=ax, node_fc="black")
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        ax, collections = xgi.draw(H, ax=ax, node_fc=["black"] * H.num_nodes)
+
+    plt.close("all")

xgi/drawing/draw.py

@@ -7,6 +7,7 @@
 import numpy as np
 import seaborn as sb  # for cmap "crest"
 from matplotlib import cm
+from matplotlib.colors import is_color_like
 from matplotlib.patches import FancyArrowPatch
 from mpl_toolkits.mplot3d.art3d import (
     Line3DCollection,
@@ -433,10 +434,6 @@ def draw_nodes(
     settings.update(params)
     settings.update(kwargs)
 
-    # avoid matplotlib scatter UserWarning "Parameters 'cmap' will be ignored"
-    if isinstance(node_fc, str):
-        node_fc_cmap = None
-
     ax, pos = _draw_init(H, ax, pos)
 
     # convert pos to format convenient for scatter
@@ -450,6 +447,12 @@ def draw_nodes(
     node_fc = _draw_arg_to_arr(node_fc)
     node_lw = _draw_arg_to_arr(node_lw)
 
+    # avoid matplotlib scatter UserWarning "Parameters 'cmap' will be ignored"
+    if isinstance(node_fc, str) or (
+        isinstance(node_fc, np.ndarray) and is_color_like(node_fc[0])
+    ):
+        node_fc_cmap = None
+
     # check validity of input values
     if np.any(node_size < 0):
         raise ValueError("node_size cannot contain negative values.")