import contextlib

import functools

import inspect

import os

from platform import uname

from pathlib import Path

import shutil

import string

import sys

import warnings

from packaging.version import parse as parse_version

import matplotlib.style

import matplotlib.units

import matplotlib.testing

from matplotlib import _pylab_helpers, cbook, ft2font, pyplot as plt, ticker

from matplotlib.figure import Figure

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")

def _check_freetype_version(ver):

if ver is None:

return True

if isinstance(ver, str):

ver = (ver, ver)

ver = [parse_version(x) for x in ver]

found = parse_version(ft2font.__freetype_version__)

return ver[0] <= found <= ver[1]

def _checked_on_freetype_version(required_freetype_version):

import pytest

return pytest.mark.xfail(

not _check_freetype_version(required_freetype_version),

reason=f"Mismatched version of freetype. "

f"Test requires '{required_freetype_version}', "

f"you have '{ft2font.__freetype_version__}'",

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)

@contextlib.contextmanager

def _collect_new_figures():

"""

After::

with _collect_new_figures() as figs:

some_code()

the list *figs* contains the figures that have been created during the

execution of ``some_code``, sorted by figure number.

"""

managers = _pylab_helpers.Gcf.figs

preexisting = [manager for manager in managers.values()]

new_figs = []

try:

yield new_figs

finally:

new_managers = sorted([manager for manager in managers.values()

if manager not in preexisting],

key=lambda manager: manager.num)

new_figs[:] = [manager.canvas.figure for manager in new_managers]

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)

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:

if 'microsoft' in uname().release.lower():

raise OSError # On WSL, symlink breaks silently

if sys.platform == 'emscripten':

raise OSError

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, fig, baseline, extension, *, _lock=False):

__tracebackhide__ = True

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:

try:

fig.savefig(actual_path, **kwargs)

finally:

# Matplotlib has an autouse fixture to close figures, but this

# makes things more convenient for third-party users.

plt.close(fig)

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

KEYWORD_ONLY = inspect.Parameter.KEYWORD_ONLY

def decorator(func):

old_sig = inspect.signature(func)

@functools.wraps(func)

@pytest.mark.parametrize('extension', extensions)

@matplotlib.style.context(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

if extension not in comparable_formats():

reason = {

'gif': 'because ImageMagick is not installed',

'pdf': 'because Ghostscript is not installed',

'eps': 'because Ghostscript is not installed',

'svg': 'because Inkscape is not installed',

}.get(extension, 'on this system')

pytest.skip(f"Cannot compare {extension} files {reason}")

img = _ImageComparisonBase(func, tol=tol, remove_text=remove_text,

savefig_kwargs=savefig_kwargs)

matplotlib.testing.set_font_settings_for_testing()

with _collect_new_figures() as figs:

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(figs) == len(our_baseline_images), (

f"Test generated {len(figs)} images but there are "

f"{len(our_baseline_images)} baseline images")

for fig, baseline in zip(figs, our_baseline_images):

img.compare(fig, 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: 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", ), 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"]

The extensions to test. Supported extensions are "png", "pdf", "svg".

Testing with the one default extension is sufficient if the output is not

format dependent, e.g. if you test that a ``bar()`` plot yields the same

result as some manually placed Rectangles. You should use all extensions

if a renderer property is involved, e.g. correct alpha blending.

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_test' and 'fig_ref', 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)

fig_test = Figure()

fig_ref = Figure()

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

if len(fig_test.get_children()) == 1 and len(fig_ref.get_children()) == 1:

# no artists have been added. The only child is fig.patch.

raise RuntimeError("Both figures are empty. Make sure you are "

"plotting to fig_test or fig_ref.")

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

)

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(inspect.getfile(func))

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