changes to the test_backend_pgf to work according to the flag

SidharthBansal · SidharthBansal · commit 317f6f3a33b8 · 2020-08-23T19:13:35.000+05:30
diff --git a/lib/matplotlib/tests/test_backend_pgf.py b/lib/matplotlib/tests/test_backend_pgf.py
@@ -14,6 +14,7 @@
 from matplotlib.testing.compare import compare_images, ImageComparisonFailure
 from matplotlib.testing.decorators import image_comparison, _image_directories
 from matplotlib.backends.backend_pgf import PdfPages, common_texification
+import contextlib
 
 baseline_dir, result_dir = _image_directories(lambda: 'dummy func')
 
@@ -51,16 +52,38 @@ def _has_sfmath():
             and subprocess.run(["kpsewhich", "sfmath.sty"],
                                stdout=subprocess.PIPE).returncode == 0)
 
-
-def compare_figure(fname, savefig_kwargs={}, tol=0):
+def create_baseline(fname):
+        src_path = result_dir / fname
+        dest_file = Path(baseline_dir / src_path.name)
+        try:
+            if dest_file.exists():
+                return dest_file
+            Path(dest_file).parent.mkdir(parents=True, exist_ok=True)
+            try:
+                os.symlink(src_path, dest_file)
+            except OSError:  # On Windows, symlink *may* be unavailable.
+                shutil.copyfile(src_path, dest_file)
+        except OSError as err:
+            raise ImageComparisonFailure(
+                f"Missing baseline image {dest_file} because the "
+                f"following file cannot be accessed: "
+                f"{src_path}") from err
+        return dest_file
+
+
+# Cannot use Image Comparison decorator because rc_context calls save_figure before releasing memory whereas image
+# decorator is returning it afterwards.
+def compare_figure(fname, savefig_kwargs={}, tol=0, generating=False):
     actual = os.path.join(result_dir, fname)
     plt.savefig(actual, **savefig_kwargs)
-
-    expected = os.path.join(result_dir, "expected_%s" % fname)
-    shutil.copyfile(os.path.join(baseline_dir, fname), expected)
-    err = compare_images(expected, actual, tol=tol)
-    if err:
-        raise ImageComparisonFailure(err)
+    if generating:
+        expected_creation_path = create_baseline(fname)
+    else:
+        expected = os.path.join(result_dir, "expected_%s" % fname)
+        shutil.copyfile(os.path.join(baseline_dir, fname), expected)
+        err = compare_images(expected, actual, tol=tol)
+        if err:
+            raise ImageComparisonFailure(err)
 
 
 def create_figure():
@@ -135,7 +158,8 @@ def test_pdflatex():
 @pytest.mark.skipif(not _has_sfmath(), reason='needs sfmath.sty')
 @pytest.mark.style('default')
 @pytest.mark.backend('pgf')
-def test_rcupdate():
+@pytest.mark.generate_images
+def test_rcupdate(request):
     rc_sets = [{'font.family': 'sans-serif',
                 'font.size': 30,
                 'figure.subplot.left': .2,
@@ -152,10 +176,11 @@ def test_rcupdate():
                                  '\\usepackage[T1]{fontenc}'
                                  '\\usepackage{sfmath}')}]
     tol = [6, 0]
+    generate_images = request.config.getoption("--generate_images")
     for i, rc_set in enumerate(rc_sets):
         with mpl.rc_context(rc_set):
             create_figure()
-            compare_figure('pgf_rcupdate%d.pdf' % (i + 1), tol=tol[i])
+            compare_figure('pgf_rcupdate%d.pdf' % (i + 1), tol=tol[i], generating=generate_images)
 
 
 # test backend-side clipping, since large numbers are not supported by TeX
@@ -193,7 +218,8 @@ def test_mixedmode():
 @needs_xelatex
 @pytest.mark.style('default')
 @pytest.mark.backend('pgf')
-def test_bbox_inches():
+@pytest.mark.generate_images
+def test_bbox_inches(request):
     rc_xelatex = {'font.family': 'serif',
                   'pgf.rcfonts': False}
     mpl.rcParams.update(rc_xelatex)
@@ -205,10 +231,10 @@ def test_bbox_inches():
     ax2 = fig.add_subplot(122)
     ax2.plot(range(5))
     plt.tight_layout()
-
+    generate_images = request.config.getoption("--generate_images")
     bbox = ax1.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
     compare_figure('pgf_bbox_inches.pdf', savefig_kwargs={'bbox_inches': bbox},
-                   tol=0)
+                   tol=0, generating=generate_images)
 
 
 @pytest.mark.style('default')
