Merge pull request #8344 from dstansby/arrow-test

tacaswell · web-flow · commit d16c4a16c503 · 2017-04-11T23:41:02.000-04:00
FIX/TST: Add simple ax.arrow test
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -1252,7 +1252,7 @@ def __init__(self, x, y, dx, dy, width=0.001, length_includes_head=False,
                     # The half-arrows contain the midpoint of the stem,
                     # which we can omit from the full arrow. Including it
                     # twice caused a problem with xpdf.
-                    coords = np.concatenate([left_half_arrow[:-2],
+                    coords = np.concatenate([left_half_arrow[:-1],
                                              right_half_arrow[-2::-1]])
                 else:
                     raise ValueError("Got unknown shape: %s" % shape)
diff --git a/lib/matplotlib/tests/baseline_images/test_axes/arrow_simple.png b/lib/matplotlib/tests/baseline_images/test_axes/arrow_simple.png
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -3,7 +3,7 @@
 
 import six
 from six.moves import xrange
-from itertools import chain
+from itertools import chain, product
 from distutils.version import LooseVersion
 import io
 
@@ -263,6 +263,34 @@ def test_basic_annotate():
                 xytext=(3, 3), textcoords='offset points')
 
 
+@image_comparison(baseline_images=['arrow_simple'],
+                  extensions=['png'], remove_text=True)
+def test_arrow_simple():
+    # Simple image test for ax.arrow
+    # kwargs that take discrete values
+    length_includes_head = (True, False)
+    shape = ('full', 'left', 'right')
+    head_starts_at_zero = (True, False)
+    # Create outer product of values
+    kwargs = list(product(length_includes_head, shape, head_starts_at_zero))
+
+    fig, axs = plt.subplots(3, 4)
+    for i, (ax, kwarg) in enumerate(zip(axs.flatten(), kwargs)):
+        ax.set_xlim(-2, 2)
+        ax.set_ylim(-2, 2)
+        # Unpack kwargs
+        (length_includes_head, shape, head_starts_at_zero) = kwarg
+        theta = 2 * np.pi * i / 12
+        # Draw arrow
+        ax.arrow(0, 0, np.sin(theta), np.cos(theta),
+                 width=theta/100,
+                 length_includes_head=length_includes_head,
+                 shape=shape,
+                 head_starts_at_zero=head_starts_at_zero,
+                 head_width=theta / 10,
+                 head_length=theta / 10)
+
+
 def test_annotate_default_arrow():
     # Check that we can make an annotation arrow with only default properties.
     fig, ax = plt.subplots()
