45 lines
1.3 KiB
Python
45 lines
1.3 KiB
Python
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import io
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import pkgutil
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import pytest
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from altair.utils.execeval import eval_block
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from altair import examples
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@pytest.fixture
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def require_altair_saver_png():
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try:
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import altair_saver # noqa: F401
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except ImportError:
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pytest.skip("altair_saver not importable; cannot run saver tests")
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if "png" not in altair_saver.available_formats('vega-lite'):
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pytest.skip("altair_saver not configured to save to png")
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def iter_example_filenames():
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for importer, modname, ispkg in pkgutil.iter_modules(examples.__path__):
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if ispkg or modname.startswith('_'):
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continue
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yield modname + '.py'
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@pytest.mark.parametrize('filename', iter_example_filenames())
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def test_examples(filename: str):
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source = pkgutil.get_data(examples.__name__, filename)
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chart = eval_block(source)
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if chart is None:
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raise ValueError("Example file should define chart in its final "
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"statement.")
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chart.to_dict()
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@pytest.mark.parametrize('filename', iter_example_filenames())
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def test_render_examples_to_png(require_altair_saver_png, filename):
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source = pkgutil.get_data(examples.__name__, filename)
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chart = eval_block(source)
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out = io.BytesIO()
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chart.save(out, format="png")
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assert out.getvalue().startswith(b'\x89PNG')
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