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

import matplotlib.style

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

@contextlib.contextmanager

def _cleanup_cm():

orig_units_registry = matplotlib.units.registry.copy()

try:

with warnings.catch_warnings(), matplotlib.rc_context():

yield

finally:

matplotlib.units.registry.clear()

matplotlib.units.registry.update(orig_units_registry)

plt.close("all")

class CleanupTestCase(unittest.TestCase):

"""A wrapper for unittest.TestCase that includes cleanup operations."""

@classmethod

def setUpClass(cls):

cls._cm = _cleanup_cm().__enter__()

@classmethod

def tearDownClass(cls):

cls._cm.__exit__(None, None, None)

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(), matplotlib.style.context(style):

yield from func(*args, **kwargs)

else:

@functools.wraps(func)

def wrapped_callable(*args, **kwargs):

with _cleanup_cm(), matplotlib.style.context(style):

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

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)

def remove_ticks_and_titles(figure):

figure.suptitle("")

null_formatter = ticker.NullFormatter()

def remove_ticks(ax):

"""Remove ticks in *ax* and all its child 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

for child in ax.child_axes:

remove_ticks(child)

for ax in figure.get_axes():

remove_ticks(ax)

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 / orig_expected_path.name, '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 contextlib.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)

@pytest.mark.style(style)

@_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):

img.compare(idx, 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

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)

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.

Raises

------

RuntimeError

If any new figures are created (and not subsequently closed) inside

the test function.

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 request.node.name

if c in ALLOWED_CHARS)

try:

fig_test = plt.figure("test")

fig_ref = plt.figure("reference")

# Keep track of number of open figures, to make sure test

# doesn't create any new ones

n_figs = len(plt.get_fignums())

func(*args, fig_test=fig_test, fig_ref=fig_ref, **kwargs)

if len(plt.get_fignums()) > n_figs:

raise RuntimeError('Number of open figures changed during '

'test. Make sure you are plotting to '

'fig_test or fig_ref, or if this is '

'deliberate explicitly close the '

'new figure(s) inside the test.')

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 param.name 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 ``foo.bar.test_baz``, 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