Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/skimage/_shared/testing.py

@@ -0,0 +1,270 @@
+"""
+Testing utilities.
+"""
+
+import os
+import re
+import struct
+import threading
+import functools
+from tempfile import NamedTemporaryFile
+
+import numpy as np
+from numpy import testing
+from numpy.testing import (assert_array_equal, assert_array_almost_equal,
+                           assert_array_less, assert_array_almost_equal_nulp,
+                           assert_equal, TestCase, assert_allclose,
+                           assert_almost_equal, assert_, assert_warns,
+                           assert_no_warnings)
+
+import warnings
+
+from .. import data, io
+from ..util import img_as_uint, img_as_float, img_as_int, img_as_ubyte
+import pytest
+from ._warnings import expected_warnings
+
+
+SKIP_RE = re.compile(r"(\s*>>>.*?)(\s*)#\s*skip\s+if\s+(.*)$")
+
+skipif = pytest.mark.skipif
+xfail = pytest.mark.xfail
+parametrize = pytest.mark.parametrize
+raises = pytest.raises
+fixture = pytest.fixture
+
+# true if python is running in 32bit mode
+# Calculate the size of a void * pointer in bits
+# https://docs.python.org/3/library/struct.html
+arch32 = struct.calcsize("P") * 8 == 32
+
+
+def assert_less(a, b, msg=None):
+    message = "%r is not lower than %r" % (a, b)
+    if msg is not None:
+        message += ": " + msg
+    assert a < b, message
+
+
+def assert_greater(a, b, msg=None):
+    message = "%r is not greater than %r" % (a, b)
+    if msg is not None:
+        message += ": " + msg
+    assert a > b, message
+
+
+def doctest_skip_parser(func):
+    """ Decorator replaces custom skip test markup in doctests
+
+    Say a function has a docstring::
+
+        >>> something, HAVE_AMODULE, HAVE_BMODULE = 0, False, False
+        >>> something # skip if not HAVE_AMODULE
+        0
+        >>> something # skip if HAVE_BMODULE
+        0
+
+    This decorator will evaluate the expression after ``skip if``.  If this
+    evaluates to True, then the comment is replaced by ``# doctest: +SKIP``. If
+    False, then the comment is just removed. The expression is evaluated in the
+    ``globals`` scope of `func`.
+
+    For example, if the module global ``HAVE_AMODULE`` is False, and module
+    global ``HAVE_BMODULE`` is False, the returned function will have docstring::
+
+        >>> something # doctest: +SKIP
+        >>> something + else # doctest: +SKIP
+        >>> something # doctest: +SKIP
+
+    """
+    lines = func.__doc__.split('\n')
+    new_lines = []
+    for line in lines:
+        match = SKIP_RE.match(line)
+        if match is None:
+            new_lines.append(line)
+            continue
+        code, space, expr = match.groups()
+
+        try:
+            # Works as a function decorator
+            if eval(expr, func.__globals__):
+                code = code + space + "# doctest: +SKIP"
+        except AttributeError:
+            # Works as a class decorator
+            if eval(expr, func.__init__.__globals__):
+                code = code + space + "# doctest: +SKIP"
+
+        new_lines.append(code)
+    func.__doc__ = "\n".join(new_lines)
+    return func
+
+
+def roundtrip(image, plugin, suffix):
+    """Save and read an image using a specified plugin"""
+    if '.' not in suffix:
+        suffix = '.' + suffix
+    temp_file = NamedTemporaryFile(suffix=suffix, delete=False)
+    fname = temp_file.name
+    temp_file.close()
+    io.imsave(fname, image, plugin=plugin)
+    new = io.imread(fname, plugin=plugin)
+    try:
+        os.remove(fname)
+    except Exception:
+        pass
+    return new
+
+
+def color_check(plugin, fmt='png'):
+    """Check roundtrip behavior for color images.
+
+    All major input types should be handled as ubytes and read
+    back correctly.
+    """
+    img = img_as_ubyte(data.chelsea())
+    r1 = roundtrip(img, plugin, fmt)
+    testing.assert_allclose(img, r1)
+
+    img2 = img > 128
+    r2 = roundtrip(img2, plugin, fmt)
+    testing.assert_allclose(img2, r2.astype(bool))
+
+    img3 = img_as_float(img)
+    r3 = roundtrip(img3, plugin, fmt)
+    testing.assert_allclose(r3, img)
+
+    img4 = img_as_int(img)
+    if fmt.lower() in (('tif', 'tiff')):
+        img4 -= 100
+        r4 = roundtrip(img4, plugin, fmt)
+        testing.assert_allclose(r4, img4)
+    else:
+        r4 = roundtrip(img4, plugin, fmt)
+        testing.assert_allclose(r4, img_as_ubyte(img4))
+
+    img5 = img_as_uint(img)
+    r5 = roundtrip(img5, plugin, fmt)
+    testing.assert_allclose(r5, img)
+
+
+def mono_check(plugin, fmt='png'):
+    """Check the roundtrip behavior for images that support most types.
+
+    All major input types should be handled.
+    """
+
+    img = img_as_ubyte(data.moon())
+    r1 = roundtrip(img, plugin, fmt)
+    testing.assert_allclose(img, r1)
+
+    img2 = img > 128
+    r2 = roundtrip(img2, plugin, fmt)
+    testing.assert_allclose(img2, r2.astype(bool))
+
+    img3 = img_as_float(img)
+    r3 = roundtrip(img3, plugin, fmt)
+    if r3.dtype.kind == 'f':
+        testing.assert_allclose(img3, r3)
+    else:
+        testing.assert_allclose(r3, img_as_uint(img))
+
+    img4 = img_as_int(img)
+    if fmt.lower() in (('tif', 'tiff')):
+        img4 -= 100
+        r4 = roundtrip(img4, plugin, fmt)
+        testing.assert_allclose(r4, img4)
+    else:
+        r4 = roundtrip(img4, plugin, fmt)
+        testing.assert_allclose(r4, img_as_uint(img4))
+
+    img5 = img_as_uint(img)
+    r5 = roundtrip(img5, plugin, fmt)
+    testing.assert_allclose(r5, img5)
+
+
+def setup_test():
+    """Default package level setup routine for skimage tests.
+
+    Import packages known to raise warnings, and then
+    force warnings to raise errors.
+
+    Also set the random seed to zero.
+    """
+    warnings.simplefilter('default')
+
+    from scipy import signal, ndimage, special, optimize, linalg
+    from scipy.io import loadmat
+    from skimage import viewer
+
+    np.random.seed(0)
+
+    warnings.simplefilter('error')
+
+
+def teardown_test():
+    """Default package level teardown routine for skimage tests.
+
+    Restore warnings to default behavior
+    """
+    warnings.simplefilter('default')
+
+
+def fetch(data_filename):
+    """Attempt to fetch data, but if unavailable, skip the tests."""
+    try:
+        return data._fetch(data_filename)
+    except (ConnectionError, ModuleNotFoundError):
+        pytest.skip(f'Unable to download {data_filename}')
+
+
+def test_parallel(num_threads=2, warnings_matching=None):
+    """Decorator to run the same function multiple times in parallel.
+
+    This decorator is useful to ensure that separate threads execute
+    concurrently and correctly while releasing the GIL.
+
+    Parameters
+    ----------
+    num_threads : int, optional
+        The number of times the function is run in parallel.
+
+    warnings_matching: list or None
+        This parameter is passed on to `expected_warnings` so as not to have
+        race conditions with the warnings filters. A single
+        `expected_warnings` context manager is used for all threads.
+        If None, then no warnings are checked.
+
+    """
+
+    assert num_threads > 0
+
+    def wrapper(func):
+        @functools.wraps(func)
+        def inner(*args, **kwargs):
+            with expected_warnings(warnings_matching):
+                threads = []
+                for i in range(num_threads - 1):
+                    thread = threading.Thread(target=func, args=args,
+                                              kwargs=kwargs)
+                    threads.append(thread)
+                for thread in threads:
+                    thread.start()
+
+                result = func(*args, **kwargs)
+
+                for thread in threads:
+                    thread.join()
+
+                return result
+
+        return inner
+
+    return wrapper
+
+
+if __name__ == '__main__':
+    color_check('pil')
+    mono_check('pil')
+    mono_check('pil', 'bmp')
+    mono_check('pil', 'tiff')