TST: add an figure comparison test that exercise fallback

tacaswell · tacaswell · commit 884dd033cc02 · 2022-07-07T18:51:35.000-04:00
diff --git a/lib/matplotlib/tests/test_font_manager.py b/lib/matplotlib/tests/test_font_manager.py
@@ -132,31 +132,6 @@ def test_find_noto():
         fig.savefig(BytesIO(), format=fmt)
 
 
-def test_fallback_smoke():
-    fp = FontProperties(family=["WenQuanYi Zen Hei"])
-    if Path(findfont(fp)).name != "wqy-zenhei.ttc":
-        pytest.skip("Font wqy-zenhei.ttc may be missing")
-
-    fp = FontProperties(family=["Noto Sans CJK JP"])
-    if Path(findfont(fp)).name != "NotoSansCJK-Regular.ttc":
-        pytest.skip("Noto Sans CJK JP font may be missing.")
-
-    plt.rcParams['font.size'] = 20
-    fig = plt.figure(figsize=(4.75, 1.85))
-    fig.text(0.05, 0.45, "There are 几个汉字 in between!",
-             family=['DejaVu Sans', "Noto Sans CJK JP"])
-    fig.text(0.05, 0.25, "There are 几个汉字 in between!",
-             family=['DejaVu Sans', "WenQuanYi Zen Hei"])
-    fig.text(0.05, 0.65, "There are 几个汉字 in between!",
-             family=["Noto Sans CJK JP"])
-    fig.text(0.05, 0.85, "There are 几个汉字 in between!",
-             family=["WenQuanYi Zen Hei"])
-
-    # TODO enable fallback for other backends!
-    for fmt in ['png', 'raw']:  # ["svg", "pdf", "ps"]:
-        fig.savefig(BytesIO(), format=fmt)
-
-
 def test_find_invalid(tmpdir):
     tmp_path = Path(tmpdir)
 
@@ -347,24 +322,3 @@ def test_get_font_names():
     assert set(available_fonts) == set(mpl_font_names)
     assert len(available_fonts) == len(mpl_font_names)
     assert available_fonts == mpl_font_names
-
-
-def test_fallback_errors():
-    file_name = findfont('DejaVu Sans')
-
-    with pytest.raises(TypeError, match="Fallback list must be a list"):
-        # failing to be a list will fail before the 0
-        ft2font.FT2Font(file_name, _fallback_list=(0,))
-
-    with pytest.raises(
-            TypeError, match="Fallback fonts must be FT2Font objects."
-    ):
-        ft2font.FT2Font(file_name, _fallback_list=[0])
-
-
-def test_ft2font_positive_hinting_factor():
-    file_name = findfont('DejaVu Sans')
-    with pytest.raises(
-            ValueError, match="hinting_factor must be greater than 0"
-    ):
-        ft2font.FT2Font(file_name, 0)
diff --git a/lib/matplotlib/tests/test_ft2font.py b/lib/matplotlib/tests/test_ft2font.py
@@ -0,0 +1,78 @@
+from pathlib import Path
+import io
+import pytest
+
+from matplotlib import ft2font
+from matplotlib.testing.decorators import check_figures_equal
+import matplotlib.font_manager as fm
+import matplotlib.pyplot as plt
+
+
+def test_fallback_errors():
+    file_name = fm.findfont('DejaVu Sans')
+
+    with pytest.raises(TypeError, match="Fallback list must be a list"):
+        # failing to be a list will fail before the 0
+        ft2font.FT2Font(file_name, _fallback_list=(0,))
+
+    with pytest.raises(
+            TypeError, match="Fallback fonts must be FT2Font objects."
+    ):
+        ft2font.FT2Font(file_name, _fallback_list=[0])
+
+
+def test_ft2font_positive_hinting_factor():
+    file_name = fm.findfont('DejaVu Sans')
+    with pytest.raises(
+            ValueError, match="hinting_factor must be greater than 0"
+    ):
+        ft2font.FT2Font(file_name, 0)
+
+
+def test_fallback_smoke():
+    fp = fm.FontProperties(family=["WenQuanYi Zen Hei"])
+    if Path(fm.findfont(fp)).name != "wqy-zenhei.ttc":
+        pytest.skip("Font wqy-zenhei.ttc may be missing")
+
+    fp = fm.FontProperties(family=["Noto Sans CJK JP"])
+    if Path(fm.findfont(fp)).name != "NotoSansCJK-Regular.ttc":
+        pytest.skip("Noto Sans CJK JP font may be missing.")
+
+    plt.rcParams['font.size'] = 20
+    fig = plt.figure(figsize=(4.75, 1.85))
+    fig.text(0.05, 0.45, "There are 几个汉字 in between!",
+             family=['DejaVu Sans', "Noto Sans CJK JP"])
+    fig.text(0.05, 0.25, "There are 几个汉字 in between!",
+             family=['DejaVu Sans', "WenQuanYi Zen Hei"])
+    fig.text(0.05, 0.65, "There are 几个汉字 in between!",
+             family=["Noto Sans CJK JP"])
+    fig.text(0.05, 0.85, "There are 几个汉字 in between!",
+             family=["WenQuanYi Zen Hei"])
+
+    # TODO enable fallback for other backends!
+    for fmt in ['png', 'raw']:  # ["svg", "pdf", "ps"]:
+        fig.savefig(io.BytesIO(), format=fmt)
+
+
+@pytest.mark.parametrize('ch_font',
+                         [("WenQuanYi Zen Hei",  "wqy-zenhei.ttc"),
+                          ("Noto Sans CJK JP", "NotoSansCJK-Regular.ttc")]
+                         )
+@check_figures_equal(extensions=["png"])
+def test_font_fallback_chinese(fig_test, fig_ref, ch_font):
+    family_name, file_name = ch_font
+    fp = fm.FontProperties(family=[family_name])
+    if Path(fm.findfont(fp)).name != file_name:
+        pytest.skip(f"Font {family_name} ({file_name}) is missing")
+
+    text = ["There are", "几个汉字", "in between!"]
+
+    plt.rcParams["font.size"] = 20
+    test_fonts = [["DejaVu Sans", family_name]] * 3
+    ref_fonts = [["DejaVu Sans"], [family_name], ["DejaVu Sans"]]
+
+    for j, (txt, test_font, ref_font) in enumerate(
+            zip(text, test_fonts, ref_fonts)
+    ):
+        fig_ref.text(0.05, .85 - 0.15*j, txt, family=ref_font)
+        fig_test.text(0.05, .85 - 0.15*j, txt, family=test_font)
