Source code for matplotlib.testing.decorators

import contextlib
from distutils.version import StrictVersion
import functools
import inspect
import os
from pathlib import Path
import shutil
import string
import sys
import unittest
import warnings
    from contextlib import nullcontext
except ImportError:
    from contextlib import ExitStack as nullcontext  # Py3.6.

import matplotlib as mpl
import matplotlib.units
import matplotlib.testing
from matplotlib import cbook
from matplotlib import ft2font
from matplotlib import pyplot as plt
from matplotlib import ticker

from .compare import comparable_formats, compare_images, make_test_filename
from .exceptions import ImageComparisonFailure

def _cleanup_cm():
    orig_units_registry = matplotlib.units.registry.copy()
        with warnings.catch_warnings(), matplotlib.rc_context():

[docs]class CleanupTestCase(unittest.TestCase): """A wrapper for unittest.TestCase that includes cleanup operations."""
[docs] @classmethod def setUpClass(cls): cls._cm = _cleanup_cm().__enter__()
[docs] @classmethod def tearDownClass(cls): cls._cm.__exit__(None, None, None)
[docs]def cleanup(style=None): """ A decorator to ensure that any global state is reset before running a test. Parameters ---------- style : str, dict, or list, optional The style(s) to apply. Defaults to ``["classic", "_classic_test_patch"]``. """ # If cleanup is used without arguments, *style* will be a callable, and we # pass it directly to the wrapper generator. If cleanup if called with an # argument, it is a string naming a style, and the function will be passed # as an argument to what we return. This is a confusing, but somewhat # standard, pattern for writing a decorator with optional arguments. def make_cleanup(func): if inspect.isgeneratorfunction(func): @functools.wraps(func) def wrapped_callable(*args, **kwargs): with _cleanup_cm(), yield from func(*args, **kwargs) else: @functools.wraps(func) def wrapped_callable(*args, **kwargs): with _cleanup_cm(), func(*args, **kwargs) return wrapped_callable if callable(style): result = make_cleanup(style) # Default of mpl_test_settings fixture and image_comparison too. style = ["classic", "_classic_test_patch"] return result else: return make_cleanup
[docs]def check_freetype_version(ver): if ver is None: return True if isinstance(ver, str): ver = (ver, ver) ver = [StrictVersion(x) for x in ver] found = StrictVersion(ft2font.__freetype_version__) return ver[0] <= found <= ver[1]
def _checked_on_freetype_version(required_freetype_version): import pytest reason = ("Mismatched version of freetype. " "Test requires '%s', you have '%s'" % (required_freetype_version, ft2font.__freetype_version__)) return pytest.mark.xfail( not check_freetype_version(required_freetype_version), reason=reason, raises=ImageComparisonFailure, strict=False)
[docs]def remove_ticks_and_titles(figure): figure.suptitle("") null_formatter = ticker.NullFormatter() for ax in figure.get_axes(): ax.set_title("") ax.xaxis.set_major_formatter(null_formatter) ax.xaxis.set_minor_formatter(null_formatter) ax.yaxis.set_major_formatter(null_formatter) ax.yaxis.set_minor_formatter(null_formatter) try: ax.zaxis.set_major_formatter(null_formatter) ax.zaxis.set_minor_formatter(null_formatter) except AttributeError: pass
def _raise_on_image_difference(expected, actual, tol): __tracebackhide__ = True err = compare_images(expected, actual, tol, in_decorator=True) if err: for key in ["actual", "expected", "diff"]: err[key] = os.path.relpath(err[key]) raise ImageComparisonFailure( ('images not close (RMS %(rms).3f):' '\n\t%(actual)s\n\t%(expected)s\n\t%(diff)s') % err) def _skip_if_format_is_uncomparable(extension): import pytest return pytest.mark.skipif( extension not in comparable_formats(), reason='Cannot compare {} files on this system'.format(extension)) def _mark_skip_if_format_is_uncomparable(extension): import pytest if isinstance(extension, str): name = extension marks = [] elif isinstance(extension, tuple): # Extension might be a pytest ParameterSet instead of a plain string. # Unfortunately, this type is not exposed, so since it's a namedtuple, # check for a tuple instead. name, = extension.values marks = [*extension.marks] else: # Extension might be a pytest marker instead of a plain string. name, = extension.args marks = [extension.mark] return pytest.param(name, marks=[*marks, _skip_if_format_is_uncomparable(name)]) class _ImageComparisonBase: """ Image comparison base class This class provides *just* the comparison-related functionality and avoids any code that would be specific to any testing framework. """ def __init__(self, func, tol, remove_text, savefig_kwargs): self.func = func self.baseline_dir, self.result_dir = _image_directories(func) self.tol = tol self.remove_text = remove_text self.savefig_kwargs = savefig_kwargs def copy_baseline(self, baseline, extension): baseline_path = self.baseline_dir / baseline orig_expected_path = baseline_path.with_suffix(f'.{extension}') if extension == 'eps' and not orig_expected_path.exists(): orig_expected_path = orig_expected_path.with_suffix('.pdf') expected_fname = make_test_filename( self.result_dir /, 'expected') try: # os.symlink errors if the target already exists. with contextlib.suppress(OSError): os.remove(expected_fname) try: os.symlink(orig_expected_path, expected_fname) except OSError: # On Windows, symlink *may* be unavailable. shutil.copyfile(orig_expected_path, expected_fname) except OSError as err: raise ImageComparisonFailure( f"Missing baseline image {expected_fname} because the " f"following file cannot be accessed: " f"{orig_expected_path}") from err return expected_fname def compare(self, idx, baseline, extension, *, _lock=False): __tracebackhide__ = True fignum = plt.get_fignums()[idx] fig = plt.figure(fignum) if self.remove_text: remove_ticks_and_titles(fig) actual_path = (self.result_dir / baseline).with_suffix(f'.{extension}') kwargs = self.savefig_kwargs.copy() if extension == 'pdf': kwargs.setdefault('metadata', {'Creator': None, 'Producer': None, 'CreationDate': None}) lock = cbook._lock_path(actual_path) if _lock else nullcontext() with lock: fig.savefig(actual_path, **kwargs) expected_path = self.copy_baseline(baseline, extension) _raise_on_image_difference(expected_path, actual_path, self.tol) def _pytest_image_comparison(baseline_images, extensions, tol, freetype_version, remove_text, savefig_kwargs, style): """ Decorate function with image comparison for pytest. This function creates a decorator that wraps a figure-generating function with image comparison code. """ import pytest extensions = map(_mark_skip_if_format_is_uncomparable, extensions) KEYWORD_ONLY = inspect.Parameter.KEYWORD_ONLY def decorator(func): old_sig = inspect.signature(func) @functools.wraps(func) @pytest.mark.parametrize('extension', extensions) @_checked_on_freetype_version(freetype_version) @functools.wraps(func) def wrapper(*args, extension, request, **kwargs): __tracebackhide__ = True if 'extension' in old_sig.parameters: kwargs['extension'] = extension if 'request' in old_sig.parameters: kwargs['request'] = request img = _ImageComparisonBase(func, tol=tol, remove_text=remove_text, savefig_kwargs=savefig_kwargs) matplotlib.testing.set_font_settings_for_testing() func(*args, **kwargs) # If the test is parametrized in any way other than applied via # this decorator, then we need to use a lock to prevent two # processes from touching the same output file. needs_lock = any( marker.args[0] != 'extension' for marker in request.node.iter_markers('parametrize')) if baseline_images is not None: our_baseline_images = baseline_images else: # Allow baseline image list to be produced on the fly based on # current parametrization. our_baseline_images = request.getfixturevalue( 'baseline_images') assert len(plt.get_fignums()) == len(our_baseline_images), ( "Test generated {} images but there are {} baseline images" .format(len(plt.get_fignums()), len(our_baseline_images))) for idx, baseline in enumerate(our_baseline_images):, baseline, extension, _lock=needs_lock) parameters = list(old_sig.parameters.values()) if 'extension' not in old_sig.parameters: parameters += [inspect.Parameter('extension', KEYWORD_ONLY)] if 'request' not in old_sig.parameters: parameters += [inspect.Parameter("request", KEYWORD_ONLY)] new_sig = old_sig.replace(parameters=parameters) wrapper.__signature__ = new_sig # Reach a bit into pytest internals to hoist the marks from our wrapped # function. new_marks = getattr(func, 'pytestmark', []) + wrapper.pytestmark wrapper.pytestmark = new_marks return wrapper return decorator
[docs]def image_comparison(baseline_images, extensions=None, tol=0, freetype_version=None, remove_text=False, savefig_kwarg=None, # Default of mpl_test_settings fixture and cleanup too. style=("classic", "_classic_test_patch")): """ Compare images generated by the test with those specified in *baseline_images*, which must correspond, else an `ImageComparisonFailure` exception will be raised. Parameters ---------- baseline_images : list or None A list of strings specifying the names of the images generated by calls to `.Figure.savefig`. If *None*, the test function must use the ``baseline_images`` fixture, either as a parameter or with `pytest.mark.usefixtures`. This value is only allowed when using pytest. extensions : None or list of str The list of extensions to test, e.g. ``['png', 'pdf']``. If *None*, defaults to all supported extensions: png, pdf, and svg. When testing a single extension, it can be directly included in the names passed to *baseline_images*. In that case, *extensions* must not be set. In order to keep the size of the test suite from ballooning, we only include the ``svg`` or ``pdf`` outputs if the test is explicitly exercising a feature dependent on that backend (see also the `check_figures_equal` decorator for that purpose). tol : float, default: 0 The RMS threshold above which the test is considered failed. Due to expected small differences in floating-point calculations, on 32-bit systems an additional 0.06 is added to this threshold. freetype_version : str or tuple The expected freetype version or range of versions for this test to pass. remove_text : bool Remove the title and tick text from the figure before comparison. This is useful to make the baseline images independent of variations in text rendering between different versions of FreeType. This does not remove other, more deliberate, text, such as legends and annotations. savefig_kwarg : dict Optional arguments that are passed to the savefig method. style : str, dict, or list The optional style(s) to apply to the image test. The test itself can also apply additional styles if desired. Defaults to ``["classic", "_classic_test_patch"]``. """ if baseline_images is not None: # List of non-empty filename extensions. baseline_exts = [*filter(None, {Path(baseline).suffix[1:] for baseline in baseline_images})] if baseline_exts: if extensions is not None: raise ValueError( "When including extensions directly in 'baseline_images', " "'extensions' cannot be set as well") if len(baseline_exts) > 1: raise ValueError( "When including extensions directly in 'baseline_images', " "all baselines must share the same suffix") extensions = baseline_exts baseline_images = [ # Chop suffix out from baseline_images. Path(baseline).stem for baseline in baseline_images] if extensions is None: # Default extensions to test, if not set via baseline_images. extensions = ['png', 'pdf', 'svg'] if savefig_kwarg is None: savefig_kwarg = dict() # default no kwargs to savefig if sys.maxsize <= 2**32: tol += 0.06 return _pytest_image_comparison( baseline_images=baseline_images, extensions=extensions, tol=tol, freetype_version=freetype_version, remove_text=remove_text, savefig_kwargs=savefig_kwarg, style=style)
[docs]def check_figures_equal(*, extensions=("png", "pdf", "svg"), tol=0): """ Decorator for test cases that generate and compare two figures. The decorated function must take two keyword arguments, *fig_test* and *fig_ref*, and draw the test and reference images on them. After the function returns, the figures are saved and compared. This decorator should be preferred over `image_comparison` when possible in order to keep the size of the test suite from ballooning. Parameters ---------- extensions : list, default: ["png", "pdf", "svg"] The extensions to test. tol : float The RMS threshold above which the test is considered failed. Examples -------- Check that calling `.Axes.plot` with a single argument plots it against ``[0, 1, 2, ...]``:: @check_figures_equal() def test_plot(fig_test, fig_ref): fig_test.subplots().plot([1, 3, 5]) fig_ref.subplots().plot([0, 1, 2], [1, 3, 5]) """ ALLOWED_CHARS = set(string.digits + string.ascii_letters + '_-[]()') KEYWORD_ONLY = inspect.Parameter.KEYWORD_ONLY def decorator(func): import pytest _, result_dir = _image_directories(func) old_sig = inspect.signature(func) if not {"fig_test", "fig_ref"}.issubset(old_sig.parameters): raise ValueError("The decorated function must have at least the " "parameters 'fig_ref' and 'fig_test', but your " f"function has the signature {old_sig}") @pytest.mark.parametrize("ext", extensions) def wrapper(*args, ext, request, **kwargs): if 'ext' in old_sig.parameters: kwargs['ext'] = ext if 'request' in old_sig.parameters: kwargs['request'] = request file_name = "".join(c for c in if c in ALLOWED_CHARS) try: fig_test = plt.figure("test") fig_ref = plt.figure("reference") func(*args, fig_test=fig_test, fig_ref=fig_ref, **kwargs) test_image_path = result_dir / (file_name + "." + ext) ref_image_path = result_dir / (file_name + "-expected." + ext) fig_test.savefig(test_image_path) fig_ref.savefig(ref_image_path) _raise_on_image_difference( ref_image_path, test_image_path, tol=tol ) finally: plt.close(fig_test) plt.close(fig_ref) parameters = [ param for param in old_sig.parameters.values() if not in {"fig_test", "fig_ref"} ] if 'ext' not in old_sig.parameters: parameters += [inspect.Parameter("ext", KEYWORD_ONLY)] if 'request' not in old_sig.parameters: parameters += [inspect.Parameter("request", KEYWORD_ONLY)] new_sig = old_sig.replace(parameters=parameters) wrapper.__signature__ = new_sig # reach a bit into pytest internals to hoist the marks from # our wrapped function new_marks = getattr(func, "pytestmark", []) + wrapper.pytestmark wrapper.pytestmark = new_marks return wrapper return decorator
def _image_directories(func): """ Compute the baseline and result image directories for testing *func*. For test module ````, the baseline directory is at ``foo/bar/baseline_images/test_baz`` and the result directory at ``$(pwd)/result_images/test_baz``. The result directory is created if it doesn't exist. """ module_path = Path(sys.modules[func.__module__].__file__) baseline_dir = module_path.parent / "baseline_images" / module_path.stem result_dir = Path().resolve() / "result_images" / module_path.stem result_dir.mkdir(parents=True, exist_ok=True) return baseline_dir, result_dir