TST: add tests for malformed, but parsable AFM files

Author: tacaswell

lib/matplotlib/tests/test_afm.py

@@ -1,5 +1,6 @@
 from io import BytesIO
 import pytest
+import logging
 
 from matplotlib import afm
 from matplotlib import font_manager as fm
@@ -107,3 +108,30 @@ def test_bad_afm(afm_data):
     fh = BytesIO(afm_data)
     with pytest.raises(RuntimeError):
         header = afm._parse_header(fh)
+
+
+@pytest.mark.parametrize(
+    "afm_data",
+    [
+        b"""StartFontMetrics 2.0
+Comment Comments are ignored.
+Comment Creation Date:Mon Nov 13 12:34:11 GMT 2017
+Aardvark bob
+FontName MyFont-Bold
+EncodingScheme FontSpecific
+StartCharMetrics 3""",
+        b"""StartFontMetrics 2.0
+Comment Comments are ignored.
+Comment Creation Date:Mon Nov 13 12:34:11 GMT 2017
+ItalicAngle zero degrees
+FontName MyFont-Bold
+EncodingScheme FontSpecific
+StartCharMetrics 3""",
+    ],
+)
+def test_malformed_header(afm_data, caplog):
+    fh = BytesIO(afm_data)
+    with caplog.at_level(logging.ERROR):
+        header = afm._parse_header(fh)
+
+    assert len(caplog.records) == 1