Merge pull request matplotlib#21657 from anntzer/ub

Replace some image_comparisons by return-value-tests/check_figures_e…

Author: jklymak

lib/matplotlib/tests/baseline_images/test_axes/auto_numticks.png

@@ -5787,18 +5787,21 @@ def test_adjust_numtick_aspect():
     assert len(ax.yaxis.get_major_locator()()) > 2
 
 
-@image_comparison(["auto_numticks.png"], style='default')
+@mpl.style.context("default")
 def test_auto_numticks():
-    # Make tiny, empty subplots, verify that there are only 3 ticks.
-    plt.subplots(4, 4)
+    axs = plt.figure().subplots(4, 4)
+    for ax in axs.flat:  # Tiny, empty subplots have only 3 ticks.
+        assert [*ax.get_xticks()] == [*ax.get_yticks()] == [0, 0.5, 1]
 
 
-@image_comparison(["auto_numticks_log.png"], style='default')
+@mpl.style.context("default")
 def test_auto_numticks_log():
     # Verify that there are not too many ticks with a large log range.
     fig, ax = plt.subplots()
-    matplotlib.rcParams['axes.autolimit_mode'] = 'round_numbers'
+    mpl.rcParams['axes.autolimit_mode'] = 'round_numbers'
     ax.loglog([1e-20, 1e5], [1e-16, 10])
+    assert (np.log10(ax.get_xticks()) == np.arange(-26, 18, 4)).all()
+    assert (np.log10(ax.get_yticks()) == np.arange(-20, 10, 3)).all()
 
 
 def test_broken_barh_empty():

lib/matplotlib/tests/baseline_images/test_axes/auto_numticks_log.png

@@ -4,8 +4,9 @@
 import numpy as np
 import pytest
 
+import matplotlib as mpl
 from matplotlib import cm
-from matplotlib.testing.decorators import image_comparison
+from matplotlib.testing.decorators import check_figures_equal
 from matplotlib.dates import rrulewrapper
 import matplotlib.pyplot as plt
 import matplotlib.transforms as mtransforms
@@ -40,13 +41,11 @@ def test_simple():
     pickle.dump(fig, BytesIO(), pickle.HIGHEST_PROTOCOL)
 
 
-@image_comparison(
-    ['multi_pickle.png'], remove_text=True, style='mpl20', tol=0.082)
-def test_complete():
-    # Remove this line when this test image is regenerated.
-    plt.rcParams['pcolormesh.snap'] = False
-
-    fig = plt.figure('Figure with a label?', figsize=(10, 6))
+@mpl.style.context("default")
+@check_figures_equal(extensions=["png"])
+def test_complete(fig_test, fig_ref):
+    fig_ref.set_size_inches((10, 6))
+    plt.figure(fig_ref)
 
     plt.suptitle('Can you fit any more in a figure?')
 
@@ -89,25 +88,27 @@ def test_complete():
     plt.subplot(3, 3, 9)
     plt.errorbar(x, x * -0.5, xerr=0.2, yerr=0.4)
 
-    #
     # plotting is done, now test its pickle-ability
-    #
-    result_fh = BytesIO()
-    pickle.dump(fig, result_fh, pickle.HIGHEST_PROTOCOL)
-
-    plt.close('all')
-
-    # make doubly sure that there are no figures left
-    assert plt._pylab_helpers.Gcf.figs == {}
-
-    # wind back the fh and load in the figure
-    result_fh.seek(0)
-    fig = pickle.load(result_fh)
-
-    # make sure there is now a figure manager
-    assert plt._pylab_helpers.Gcf.figs != {}
-
-    assert fig.get_label() == 'Figure with a label?'
+    pkl = BytesIO()
+    pickle.dump(fig_ref, pkl, pickle.HIGHEST_PROTOCOL)
+    loaded = pickle.loads(pkl.getbuffer())
+    loaded.canvas.draw()
+
+    fig_test.set_size_inches(loaded.get_size_inches())
+    fig_test.figimage(loaded.canvas.renderer.buffer_rgba())
+
+    plt.close(loaded)
+
+
+def test_gcf():
+    fig = plt.figure("a label")
+    buf = BytesIO()
+    pickle.dump(fig, buf, pickle.HIGHEST_PROTOCOL)
+    plt.close("all")
+    assert plt._pylab_helpers.Gcf.figs == {}  # No figures must be left.
+    fig = pickle.loads(buf.getbuffer())
+    assert plt._pylab_helpers.Gcf.figs != {}  # A manager is there again.
+    assert fig.get_label() == "a label"
 
 
 def test_no_pyplot():