Try to install the Noto Sans CJK font

On Linux and Mac. Add a font_manager test that loads the font and
uses it. This could be useful in testing the multi-font support
(matplotlib#20740 etc).

I couldn't get the font installed on Windows. There is a Chocolatey
installer that installs all of the Noto fonts, which takes a really
long time to run.

.circleci/config.yml

@@ -59,6 +59,7 @@ commands:
               fonts-crosextra-carlito \
               fonts-freefont-otf \
               fonts-humor-sans \
+              fonts-noto-cjk \
               optipng
 
   fonts-install:

.github/workflows/tests.yml

@@ -65,6 +65,7 @@ jobs:
               cm-super \
               dvipng \
               ffmpeg \
+              fonts-noto-cjk \
               gdb \
               gir1.2-gtk-3.0 \
               graphviz \
@@ -101,6 +102,8 @@ jobs:
             ;;
           macOS)
             brew install ccache
+            brew tap homebrew/cask-fonts
+            brew install font-noto-sans-cjk-sc
             ;;
           esac
 

azure-pipelines.yml

@@ -82,6 +82,7 @@ stages:
               cm-super \
               dvipng \
               ffmpeg \
+              fonts-noto-cjk \
               gdb \
               gir1.2-gtk-3.0 \
               graphviz \
@@ -102,6 +103,8 @@ stages:
           darwin)
             brew install --cask xquartz
             brew install pkg-config ffmpeg imagemagick mplayer ccache
+            brew tap homebrew/cask-fonts
+            brew install font-noto-sans-cjk-sc
             ;;
           win32)
             ;;

lib/matplotlib/tests/test_font_manager.py

@@ -101,7 +101,7 @@ def test_utf16m_sfnt():
         entry = next(entry for entry in fontManager.ttflist
                      if Path(entry.fname).name == "seguisbi.ttf")
     except StopIteration:
-        pytest.skip("Couldn't find font to test against.")
+        pytest.skip("Couldn't find seguisbi.ttf font to test against.")
     else:
         # Check that we successfully read "semibold" from the font's sfnt table
         # and set its weight accordingly.
@@ -111,14 +111,25 @@ def test_utf16m_sfnt():
 def test_find_ttc():
     fp = FontProperties(family=["WenQuanYi Zen Hei"])
     if Path(findfont(fp)).name != "wqy-zenhei.ttc":
-        pytest.skip("Font may be missing")
-
+        pytest.skip("Font wqy-zenhei.ttc may be missing")
     fig, ax = plt.subplots()
     ax.text(.5, .5, "\N{KANGXI RADICAL DRAGON}", fontproperties=fp)
     for fmt in ["raw", "svg", "pdf", "ps"]:
         fig.savefig(BytesIO(), format=fmt)
 
 
+def test_find_noto():
+    fp = FontProperties(family=["Noto Sans CJK SC", "Noto Sans CJK JP"])
+    name = Path(findfont(fp)).name
+    if name not in ("NotoSansCJKsc-Regular.otf", "NotoSansCJK-Regular.ttc"):
+        pytest.skip(f"Noto Sans CJK SC font may be missing (found {name})")
+
+    fig, ax = plt.subplots()
+    ax.text(0.5, 0.5, 'Hello, 你好', fontproperties=fp)
+    for fmt in ["raw", "svg", "pdf", "ps"]:
+        fig.savefig(BytesIO(), format=fmt)
+
+
 def test_find_invalid(tmpdir):
     tmp_path = Path(tmpdir)