Failing test with python 3.10

[dvzrv]

Hi! We're currently rebuilding all packages against python 3.10 on Arch Linux.

Upon rebuild seqdiag 2.0.0 fails on the following:

======================================================================
ERROR: test_setup_inline_svg_is_true_with_multibytes (test_rst_directives.TestRstDirectives)
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Traceback (most recent call last):
  File "/build/seqdiag/src/seqdiag-2.0.0/src/seqdiag/tests/test_rst_directives.py", line 185, in test_setup_inline_svg_is_true_with_multibytes
    doctree = publish_doctree(text)
  File "/usr/lib/python3.10/site-packages/docutils/core.py", line 482, in publish_doctree
    output = pub.publish(enable_exit_status=enable_exit_status)
  File "/usr/lib/python3.10/site-packages/docutils/core.py", line 217, in publish
    self.document = self.reader.read(self.source, self.parser,
  File "/usr/lib/python3.10/site-packages/docutils/readers/__init__.py", line 71, in read
    self.parse()
  File "/usr/lib/python3.10/site-packages/docutils/readers/__init__.py", line 77, in parse
    self.parser.parse(self.input, document)
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/__init__.py", line 191, in parse
    self.statemachine.run(inputlines, document, inliner=self.inliner)
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/states.py", line 170, in run
    results = StateMachineWS.run(self, input_lines, input_offset,
  File "/usr/lib/python3.10/site-packages/docutils/statemachine.py", line 241, in run
    context, next_state, result = self.check_line(
  File "/usr/lib/python3.10/site-packages/docutils/statemachine.py", line 459, in check_line
    return method(match, context, next_state)
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/states.py", line 2342, in explicit_markup
    nodelist, blank_finish = self.explicit_construct(match)
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/states.py", line 2354, in explicit_construct
    return method(self, expmatch)
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/states.py", line 2096, in directive
    return self.run_directive(
  File "/usr/lib/python3.10/site-packages/docutils/parsers/rst/states.py", line 2146, in run_directive
    result = directive_instance.run()
  File "/usr/lib/python3.10/site-packages/blockdiag/utils/rst/directives.py", line 54, in decorator
    return fn(*args)
  File "/usr/lib/python3.10/site-packages/blockdiag/utils/rst/directives.py", line 178, in run
    results[0] = self.node2image(node, diagram)
  File "/usr/lib/python3.10/site-packages/blockdiag/utils/rst/directives.py", line 239, in node2image
    return self.node2image_inline_svg(node, diagram)
  File "/usr/lib/python3.10/site-packages/blockdiag/utils/rst/directives.py", line 270, in node2image_inline_svg
    content = drawer.save(size)
  File "/usr/lib/python3.10/site-packages/blockdiag/drawer.py", line 188, in save
    return self.drawer.save(self.filename, size, self.format)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/filters/linejump.py", line 182, in save
    self._run()
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/filters/linejump.py", line 109, in _run
    method(self.target, *args, **kwargs)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/svg.py", line 136, in textarea
    lines = self.textfolder(box, string, font, **kwargs)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/textfolder.py", line 66, in get
    return HorizontalTextFolder(*args, **kwargs)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/textfolder.py", line 208, in __init__
    self._result = self._lines()
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/textfolder.py", line 285, in _lines
    for folded in splittext(self, line, maxwidth, measure):
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/textfolder.py", line 41, in splittext
    textsize = metrics.textsize(text[0:i])
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/textfolder.py", line 212, in textsize
    textsize = self.drawer.textlinesize(text, self.font)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/utils/__init__.py", line 65, in func
    fn.cache[key] = fn(*args, **kwargs)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/svg.py", line 116, in textlinesize
    return self._pil_drawer.textlinesize(string, font)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/utils/__init__.py", line 65, in func
    fn.cache[key] = fn(*args, **kwargs)
  File "/usr/lib/python3.10/site-packages/blockdiag/imagedraw/png.py", line 276, in textlinesize
    size = self.draw.textsize(string, font=None)
  File "/usr/lib/python3.10/site-packages/PIL/ImageDraw.py", line 563, in textsize
    return font.getsize(text, direction, features, language, stroke_width)
  File "/usr/lib/python3.10/site-packages/PIL/ImageFont.py", line 129, in getsize
    return self.font.getsize(text)
UnicodeEncodeError: 'latin-1' codec can't encode character '\u3042' in position 0: ordinal not in range(256)
-------------------- >> begin captured logging << --------------------
PIL.PngImagePlugin: DEBUG: STREAM b'IHDR' 16 13
PIL.PngImagePlugin: DEBUG: STREAM b'IDAT' 41 1216
--------------------- >> end captured logging << ---------------------

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Ran 88 tests in 0.502s

It appears that the default font used for the operation can not render unicode (see also python-pillow/Pillow#2779).