Merge pull request #19373 from Hathaway2010/test-for-issue-19152

jklymak · web-flow · commit cd0c551ecdd3 · 2021-01-30T17:40:18.000-08:00
test for align_ylabel bug with constrained_layout
diff --git a/lib/matplotlib/tests/test_constrainedlayout.py b/lib/matplotlib/tests/test_constrainedlayout.py
@@ -521,3 +521,37 @@ def test_bboxtight():
 def test_bbox():
     fig, ax = plt.subplots(constrained_layout=True)
     ax.set_aspect(1.)
+
+
+def test_align_labels():
+    """
+    Tests for a bug in which constrained layout and align_ylabels on
+    three unevenly sized subplots, one of whose y tick labels include
+    negative numbers, drives the non-negative subplots' y labels off
+    the edge of the plot
+    """
+    fig, (ax3, ax1, ax2) = plt.subplots(3, 1, constrained_layout=True,
+                                        figsize=(6.4, 8),
+                                        gridspec_kw={"height_ratios": (1, 1,
+                                                                       0.7)})
+
+    ax1.set_ylim(0, 1)
+    ax1.set_ylabel("Label")
+
+    ax2.set_ylim(-1.5, 1.5)
+    ax2.set_ylabel("Label")
+
+    ax3.set_ylim(0, 1)
+    ax3.set_ylabel("Label")
+
+    fig.align_ylabels(axs=(ax3, ax1, ax2))
+
+    fig.canvas.draw()
+    after_align = [ax1.yaxis.label.get_window_extent(),
+                   ax2.yaxis.label.get_window_extent(),
+                   ax3.yaxis.label.get_window_extent()]
+    # ensure labels are approximately aligned
+    np.testing.assert_allclose([after_align[0].x0, after_align[2].x0],
+                               after_align[1].x0, rtol=0, atol=1e-05)
+    # ensure labels do not go off the edge
+    assert after_align[0].x0 >= 1
