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The big payoff: abolishing spoofing machinery

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This commit is contained in:
James R. Barlow
2020-06-09 00:08:20 -07:00
parent 2059e916da
commit ebbf68bd08
3 changed files with 4 additions and 116 deletions
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tests/conftest.py
+2 -113
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@@ -71,104 +71,10 @@ def have_unpaper():
TESTS_ROOT = Path(__file__).parent.resolve()
SPOOF_PATH = TESTS_ROOT / 'spoof'
PROJECT_ROOT = TESTS_ROOT
OCRMYPDF = [sys.executable, '-m', 'ocrmypdf']
WINDOWS_SHIM_TEMPLATE = """
# This is a shim for Windows that has the same effect as a symlink to the target .py
# file
import os
import subprocess
import sys
args = [sys.executable, {spoofer}, *sys.argv[1:]]
p = subprocess.run(args, check=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
sys.stdout.buffer.write(p.stdout)
sys.stderr.buffer.write(p.stderr)
sys.exit(p.returncode)
"""
assert ast.parse(WINDOWS_SHIM_TEMPLATE.format(spoofer=repr(r"C:\\Temp\\file.py")))
@pytest.helpers.register
def spoof(tmp_path_factory, **kwargs):
r"""Modify PATH to override subprocess executables
spoof(tmp_path_factory, program1='replacement', ...)
For the test suite we need a way override executables, so that we can
substitute desired results such as errors or just speed up OCR.
On POSIXish platforms we create a temporary folder with overrides that
are symlinks to the executables we want to run. We do not actually override
PATH. We also set an environment variable _OCRMYPDF_TEST_PATH, which
OCRmyPDF's subprocess wrapper will check before they use regular PATH. The
output is a folder full of executables we are overriding. We can override
multiple executables. The end result is a folder we can use in a PATH-style
lookup to override some executables:
/tmp/abcxyz/tesseract -> ocrmypdf/tests/resources/spoof/tesseract_crash.py
/tmp/abcxyz/gs -> ocrmypdf/tests/resources/spoof/gs_backflip.py
Windows needs extra help from us because usually, only the Administrator
can create symlinks. Instead we create small Python scripts that call
the programs we want, implementing the effect of a symlink. This is cleaner
than creating Windows executables or trying to use non-Python scripts.
The temporary folder generated for Windows could like:
%TEMP%\abcxyz\tesseract.py:
(script that runs ocrmypdf/tests/resources/spoof/tesseract_crash.py)
%TEMP%\abcxyz\gswin32c.py:
(script that runs ocrmypdf/tests/resources/spoof/gs_backflip.py)
%TEMP%\abcxyz\gswin64c.py:
(script that runs ocrmypdf/tests/resources/spoof/gs_backflip.py)
We also address one quirk here, that Ghostscript may be known as gswin32c
or gswin64c, depending on what the user installed (regardless of Windows
itself). On POSIX, Ghostscript is just 'gs'. We handle the special case here
too.
All of this is intimately dependent on the machinery in ocrmypdf.exec.run().
In particular, for Windows, that code has to know that if there is a .py
file, it needs to run it with Python, since Windows does not like being
asked to execute files.
We don't overload PATH directly because we have some tests where we call
ocrmypdf as a subprocess (to exercise the command line interface) and some
tests where we call it as an API.
"""
env = os.environ.copy()
slug = '-'.join(v.replace('.py', '') for v in sorted(kwargs.values()))
spoofer_base = tmp_path_factory.mktemp('spoofers')
tmpdir = Path(spoofer_base / slug)
tmpdir.mkdir(parents=True)
for replace_program, with_spoof in kwargs.items():
spoofer = SPOOF_PATH / with_spoof
if os.name != 'nt':
spoofer.chmod(0o755)
(tmpdir / replace_program).symlink_to(spoofer)
else:
py_file = WINDOWS_SHIM_TEMPLATE.format(
spoofer=repr(os.fspath(spoofer.absolute()))
)
if replace_program == 'gs':
programs = ['gswin64c', 'gswin32c']
else:
programs = [replace_program]
for prog in programs:
(tmpdir / f'{prog}.py').write_text(py_file, encoding='utf-8')
env['_OCRMYPDF_TEST_PATH'] = str(tmpdir) + os.pathsep + env['PATH']
if os.name == 'nt':
if '.py' not in env['PATHEXT'].lower():
raise EnvironmentError("PATHEXT is not configured to support .py")
return env
@pytest.fixture
def resources():
return Path(TESTS_ROOT) / 'resources'
@@ -208,12 +114,7 @@ def check_ocrmypdf(input_file, output_file, *args, env=None):
_parser, options, plugin_manager = get_parser_options_plugins(args=args)
api.check_options(options, plugin_manager)
if env:
first = env['_OCRMYPDF_TEST_PATH'].split(os.pathsep)[0]
if 'tesseract_noop' in first:
raise ValueError('noop')
else:
options.tesseract_env = env
options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = os.fspath(input_file)
assert False, 'env set'
result = api.run_pipeline(options, plugin_manager=plugin_manager, api=True)
assert result == 0
@@ -235,19 +136,7 @@ def run_ocrmypdf_api(input_file, output_file, *args, env=None):
]
_parser, options, plugin_manager = get_parser_options_plugins(args=args)
if env:
try:
first = env['_OCRMYPDF_TEST_PATH'].split(os.pathsep)[0]
if 'tesseract_noop' in first:
raise ValueError('noop')
else:
options.tesseract_env = env.copy()
options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = os.fspath(input_file)
first_path = env.get('_OCRMYPDF_TEST_PATH', '').split(os.pathsep)[0]
if 'spoof' in first_path:
assert 'gs' not in first_path, "use run_ocrmypdf() for gs"
assert 'tesseract' in first_path
except KeyError:
pass
assert False, 'env set'
if options.tesseract_env:
assert all(isinstance(v, (str, bytes)) for v in options.tesseract_env.values())
tests/test_ghostscript.py
-1
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@@ -29,7 +29,6 @@ from ocrmypdf.helpers import Resolution
check_ocrmypdf = pytest.helpers.check_ocrmypdf
run_ocrmypdf = pytest.helpers.run_ocrmypdf
run_ocrmypdf_api = pytest.helpers.run_ocrmypdf_api
spoof = pytest.helpers.spoof
@pytest.fixture