# Source code for obspy.core.util.testing

    # -*- coding: utf-8 -*-
    """
    Testing utilities for ObsPy.

    :copyright:
        The ObsPy Development Team (devs@obspy.org)
    :license:
        GNU Lesser General Public License, Version 3
        (https://www.gnu.org/copyleft/lesser.html)
    """
    from __future__ import (absolute_import, division, print_function,
                            unicode_literals)
    from future.builtins import *  # NOQA
    from future.utils import native_str

    import difflib
    from distutils.version import LooseVersion
    import doctest
    import glob
    import inspect
    import io
    import os
    import re
    import shutil
    import unittest
    import warnings

    from lxml import etree
    import numpy as np

    from obspy.core.util.base import NamedTemporaryFile, MATPLOTLIB_VERSION
    from obspy.core.util.misc import MatplotlibBackend

    # this dictionary contains the locations of checker routines that determine
    # whether the module's tests can be executed or not (e.g. because test server
    # is unreachable, necessary ports are blocked, etc.).
    # A checker routine should return either an empty string (tests can and will
    # be executed) or a message explaining why tests can not be executed (all
    # tests of corresponding module will be skipped).
    MODULE_TEST_SKIP_CHECKS = {
        'clients.seishub':
            'obspy.clients.seishub.tests.test_client._check_server_availability'}

    def add_unittests(testsuite, module_name):
        """
        Function to add all available unittests of the module with given name
        (e.g. "obspy.core") to the given unittest TestSuite.
        All submodules in the "tests" directory whose names are starting with
        ``test_`` are added.

        :type testsuite: unittest.TestSuite
        :param testsuite: testsuite to which the tests should be added
        :type module_name: str
        :param module_name: name of the module of which the tests should be added

        .. rubric:: Example

        >>> import unittest
        >>> suite = unittest.TestSuite()
        >>> add_unittests(suite, "obspy.core")
        """
        module_tests = __import__(module_name + ".tests",
                                  fromlist=[native_str("obspy")])
        filename_pattern = os.path.join(module_tests.__path__[0], "test_*.py")
        files = glob.glob(filename_pattern)
        names = (os.path.basename(file).split(".")[0] for file in files)
        module_names = (".".join([module_name, "tests", name]) for name in names)
        for _module_name in module_names:
            _module = __import__(_module_name,
                                 fromlist=[native_str("obspy")])
            testsuite.addTest(_module.suite())

    def add_doctests(testsuite, module_name):
        """
        Function to add all available doctests of the module with given name
        (e.g. "obspy.core") to the given unittest TestSuite.
        All submodules in the module's root directory are added.
        Occurring errors are shown as warnings.

        :type testsuite: unittest.TestSuite
        :param testsuite: testsuite to which the tests should be added
        :type module_name: str
        :param module_name: name of the module of which the tests should be added

        .. rubric:: Example

        >>> import unittest
        >>> suite = unittest.TestSuite()
        >>> add_doctests(suite, "obspy.core")
        """
        module = __import__(module_name, fromlist=[native_str("obspy")])
        module_path = module.__path__[0]
        module_path_len = len(module_path)

        for root, _dirs, files in os.walk(module_path):
            # skip directories without __init__.py
            if '__init__.py' not in files:
                continue
            # skip tests directories
            if root.endswith('tests'):
                continue
            # skip scripts directories
            if root.endswith('scripts'):
                continue
            # skip lib directories
            if root.endswith('lib'):
                continue
            # loop over all files
            for file in files:
                # skip if not python source file
                if not file.endswith('.py'):
                    continue
                # get module name
                parts = root[module_path_len:].split(os.sep)[1:]
                _module_name = ".".join([module_name] + parts + [file[:-3]])
                try:
                    _module = __import__(_module_name,
                                         fromlist=[native_str("obspy")])
                    testsuite.addTest(doctest.DocTestSuite(_module))
                except ValueError:
                    pass

    def write_png(arr, filename):
        """
        Custom write_png() function. matplotlib < 1.3 cannot write RGBA png files.

        Modified from https://stackoverflow.com/a/19174800
        """
        import zlib
        import struct

        buf = arr[::-1, :, :].tostring()
        height, width, _ = arr.shape

        # reverse the vertical line order and add null bytes at the start
        width_byte_4 = width * 4
        raw_data = b''.join(
            b'\x00' + buf[span:span + width_byte_4]
            for span in range((height - 1) * width * 4, -1, - width_byte_4))

        def png_pack(png_tag, data):
            chunk_head = png_tag + data
            return (struct.pack(native_str("!I"), len(data)) +
                    chunk_head +
                    struct.pack(native_str("!I"),
                                0xFFFFFFFF & zlib.crc32(chunk_head)))

        with open(filename, "wb") as fh:
            fh.write(b''.join([
                b'\x89PNG\r\n\x1a\n',
                png_pack(b'IHDR', struct.pack(native_str("!2I5B"),
                         width, height, 8, 6, 0, 0, 0)),
                png_pack(b'IDAT', zlib.compress(raw_data, 9)),
                png_pack(b'IEND', b'')]))

    def compare_images(expected, actual, tol):
        """
        Custom version of :func:`matplotlib.testing.compare.compare_images`.
        This enable ObsPy to have the same image comparison metric across
        matplotlib versions. Furthermore nose is no longer a test dependency of
        ObsPy.

        In contrast to the matplotlib version this one only works with png
        files. Fully transparent pixels will have their color set to white as
        the RGB values of fully transparent pixels change depending on the
        matplotlib version.

        Additionally this version uses a straight RMSE definition instead of the
        binned one of matplotlib.

        :param expected: The filename of the expected png file.
        :type expected: str
        :param actual: The filename of the actual png file.
        :type actual: str
        :param tol: The tolerance (a color value difference, where 255 is the
            maximal difference). The test fails if the average pixel difference
            is greater than this value.
        :type tol: float
        """
        import matplotlib.image

        if not os.path.exists(actual):
            msg = "Output image %s does not exist." % actual
            raise Exception(msg)

        if os.stat(actual).st_size == 0:
            msg = "Output image file %s is empty." % actual
            raise Exception(msg)

        if not os.path.exists(expected):
            raise IOError('Baseline image %r does not exist.' % expected)

        # Open the images. Will be opened as RGBA as float32 ranging from 0 to 1.
        expected_image = matplotlib.image.imread(native_str(expected))
        actual_image = matplotlib.image.imread(native_str(actual))
        if expected_image.shape != actual_image.shape:
            raise ImageComparisonException(
                "The shape of the received image %s is not equal to the expected "
                "shape %s." % (str(actual_image.shape),
                               str(expected_image.shape)))

        # Set the "color" of fully transparent pixels to white. This avoids the
        # issue of different "colors" for transparent pixels.
        expected_image[expected_image[..., 3] <= 0.0035] = [1.0, 1.0, 1.0, 0.0]
        actual_image[actual_image[..., 3] <= 0.0035] = [1.0, 1.0, 1.0, 0.0]

        # This deviates a bit from the matplotlib version and just calculates
        # the root mean square error of all pixel values without any other fancy
        # considerations. It also uses the alpha channel of the images. Scaled
        # by 255.
        rms = np.sqrt(np.sum((255.0 * (expected_image - actual_image)) ** 2) /
                      float(expected_image.size))

        base, ext = os.path.splitext(actual)
        diff_image = '%s-%s%s' % (base, 'failed-diff', ext)

        if rms <= tol:
            if os.path.exists(diff_image):
                os.unlink(diff_image)
            return None

        # Save diff image, expand differences in luminance domain
        abs_diff_image = np.abs(expected_image - actual_image)
        abs_diff_image *= 10.0
        save_image_np = np.clip(abs_diff_image, 0.0, 1.0)
        # Hard-code the alpha channel to fully solid
        save_image_np[:, :, 3] = 1.0

        write_png(np.uint8(save_image_np * 255.0), diff_image)

        return dict(rms=rms, expected=str(expected), actual=str(actual),
                    diff=str(diff_image), tol=tol)

    class ImageComparisonException(unittest.TestCase.failureException):
        pass

    class ImageComparison(NamedTemporaryFile):
        """
        Handles the comparison against a baseline image in an image test.

        .. note::
            Baseline images are created using matplotlib version `1.3.1`.

        :type image_path: str
        :param image_path: Path to directory where the baseline image is located
        :type image_name: str
        :param image_name: Filename (with suffix, without directory path) of the
            baseline image
        :type reltol: float, optional
        :param reltol: Multiplier that is applied to the default tolerance
            value (i.e. 10 means a 10 times harder to pass test tolerance).
        :type adjust_tolerance: bool, optional
        :param adjust_tolerance: Adjust the tolerance based on the matplotlib
            version. Can optionally be turned off to simply compare two images.
        :type plt_close_all_enter: bool
        :param plt_close_all_enter: Whether to close all open figures when entering
            context (:func:`matplotlib.pyplot.close` with "all" as first argument.
        :type plt_close_all_exit: bool
        :param plt_close_all_exit: Whether to call :func:`matplotlib.pyplot.close`
            with "all" as first argument (close all figures) or no arguments (close
            active figure). Has no effect if ``plt_close=False``.
        :type style: str
        :param style: The Matplotlib style to use to generate the figure. When
            using matplotlib 1.5 or newer, the default will be ``'classic'`` to
            ensure compatibility with older releases. On older releases, the
            default will leave the style as is. You may wish to set it to
            ``'default'`` to enable the new style from Matplotlib 2.0, or some
            alternate style, which will work back to Matplotlib 1.4.0.
        :type no_uploads: bool
        :param no_uploads: If set to ``True`` no uploads to imgur are attempted, no
            matter what (e.g. any options to ``obspy-runtests`` that would normally
            cause an upload attempt). This can be used to forcibly deactivate
            upload attempts in image tests that are expected to fail.

        The class should be used with Python's "with" statement. When setting up,
        the matplotlib rcdefaults are set to ensure consistent image testing.
        After the plotting is completed, the :meth:`ImageComparison.compare`
        method is called automatically at the end of the "with" block, comparing
        against the previously specified baseline image. This raises an exception
        (if the test fails) with the message string from
        :func:`matplotlib.testing.compare.compare_images`. Afterwards all
        temporary files are deleted automatically.

        .. note::
            If images created during the testrun should be kept after the test, set
            environment variable `OBSPY_KEEP_IMAGES` to any value before executing
            the test (e.g. with `$ OBSPY_KEEP_IMAGES= obspy-runtests` or `$
            OBSPY_KEEP_IMAGES= python test_sometest.py`). For `obspy-runtests` the
            option "--keep-images" can also be used instead of setting an
            environment variable. Created images and diffs for failing tests are
            then stored in a subfolder "testrun" under the baseline image's
            directory.
            To only keep failed images and the corresponding diff image,
            additionally set environment variable `OBSPY_KEEP_ONLY_FAILED_IMAGES`
            to any value before executing the test.

        .. rubric:: Example

        >>> from obspy import read
        >>> with ImageComparison("/my/baseline/folder", 'plot.png') as ic:
        ...     st = read()  # doctest: +SKIP
        ...     st.plot(outfile=ic.name)  # doctest: +SKIP
        ...     # image is compared against baseline image automatically
        """
        def __init__(self, image_path, image_name, reltol=1,
                     adjust_tolerance=True, plt_close_all_enter=True,
                     plt_close_all_exit=True, style=None, no_uploads=False, *args,
                     **kwargs):
            self.suffix = "." + image_name.split(".")[-1]
            super(ImageComparison, self).__init__(suffix=self.suffix, *args,
                                                  **kwargs)
            self.image_name = image_name
            self.baseline_image = os.path.join(image_path, image_name)
            self.keep_output = "OBSPY_KEEP_IMAGES" in os.environ
            self.keep_only_failed = "OBSPY_KEEP_ONLY_FAILED_IMAGES" in os.environ
            self.output_path = os.path.join(image_path, "testrun")
            self.diff_filename = "-failed-diff.".join(self.name.rsplit(".", 1))
            self.tol = reltol * 3.0
            self.plt_close_all_enter = plt_close_all_enter
            self.plt_close_all_exit = plt_close_all_exit
            self.no_uploads = no_uploads

            if (MATPLOTLIB_VERSION < [1, 4, 0] or
                    (MATPLOTLIB_VERSION[:2] == [1, 4] and style is None)):
                # No good style support.
                self.style = None
            else:
                import matplotlib.style as mstyle
                self.style = mstyle.context(style or 'classic')

            # Adjust the tolerance based on the matplotlib version. This works
            # well enough and otherwise testing is just a pain.
            #
            # The test images were generated with matplotlib tag 291091c6eb267
            # which is after https://github.com/matplotlib/matplotlib/issues/7905
            # has been fixed.
            #
            # Thus test images should accurate for matplotlib >= 2.0.1 anf
            # fairly accurate for matplotlib 1.5.x.
            if adjust_tolerance:
                # Really old versions.
                if MATPLOTLIB_VERSION < [1, 3, 0]:
                    self.tol *= 30
                # 1.3 + 1.4 have slightly different text positioning mostly.
                elif [1, 3, 0] <= MATPLOTLIB_VERSION < [1, 5, 0]:
                    self.tol *= 15
                # A few plots with mpl 1.5 have ticks and axis slightl shifted.
                # This is especially true for ticks with exponential numbers.
                # Thus the tolerance also has to be a bit higher here.
                elif [1, 5, 0] <= MATPLOTLIB_VERSION < [2, 0, 0]:
                    self.tol *= 5.0
                # Matplotlib 2.0.0 has a bug with the tick placement. This is
                # fixed in 2.0.1 but the tolerance for 2.0.0 has to be much
                # higher. 12 is an empiric value. The tick placement potentially
                # influences the axis locations and then the misfit is really
                # quite high.
                elif [2, 0, 0] <= MATPLOTLIB_VERSION < [2, 0, 1]:
                    self.tol *= 12

                # One last pass depending on the freetype version.
                # XXX: Should eventually be handled differently!
                try:
                    from matplotlib import ft2font
                except ImportError:
                    pass
                else:
                    if hasattr(ft2font, "__freetype_version__"):
                        if (LooseVersion(ft2font.__freetype_version__) >=
                                LooseVersion("2.8.0")):
                            self.tol *= 10

        def __enter__(self):
            """
            Set matplotlib defaults.
            """
            MatplotlibBackend.switch_backend("AGG", sloppy=False)

            from matplotlib import font_manager, rcParams, rcdefaults
            import locale

            try:
                locale.setlocale(locale.LC_ALL, native_str('en_US.UTF-8'))
            except Exception:
                try:
                    locale.setlocale(locale.LC_ALL,
                                     native_str('English_United States.1252'))
                except Exception:
                    msg = "Could not set locale to English/United States. " + \
                          "Some date-related tests may fail"
                    warnings.warn(msg)

            # set matplotlib builtin default settings for testing
            rcdefaults()
            if self.style is not None:
                self.style.__enter__()
            if MATPLOTLIB_VERSION >= [2, 0, 0]:
                default_font = 'DejaVu Sans'
            else:
                default_font = 'Bitstream Vera Sans'
            rcParams['font.family'] = default_font
            with warnings.catch_warnings(record=True) as w:
                warnings.filterwarnings('always', 'findfont:.*')
                font_manager.findfont(default_font)
                if w:
                    warnings.warn('Unable to find the ' + default_font + ' font. '
                                  'Plotting tests will likely fail.')
            try:
                rcParams['text.hinting'] = False
            except KeyError:
                warnings.warn("could not set rcParams['text.hinting']")
            try:
                rcParams['text.hinting_factor'] = 8
            except KeyError:
                warnings.warn("could not set rcParams['text.hinting_factor']")

            if self.plt_close_all_enter:
                import matplotlib.pyplot as plt
                try:
                    plt.close("all")
                except Exception:
                    pass
            return self

        def __exit__(self, exc_type, exc_val, exc_tb):
            """
            Remove tempfiles and store created images if OBSPY_KEEP_IMAGES
            environment variable is set.
            """
            msg = ""
            try:
                # only compare images if no exception occurred in the with
                # statement. this avoids masking previously occurred exceptions (as
                # an exception may occur in compare()). otherwise we only clean up
                # and the exception gets re-raised at the end of __exit__.
                if exc_type is None:
                    msg = self.compare()
            # we can still upload images if comparison fails on two different sized
            # images
            except ImageComparisonException as e:
                failed = True
                if "is not equal to the expected shape" in msg:
                    msg = str(e) + "\n"
                    upload_result = self._upload_images()
                    if isinstance(upload_result, dict):
                        msg += ("\tFile:      {}\n"
                                "\tExpected:  {expected}\n"
                                "\tActual:    {actual}\n"
                                "\tDiff:      {diff}\n").format(self.image_name,
                                                                **upload_result)
                    else:
                        msg += upload_result
                    raise ImageComparisonException(msg)
                raise
            # we can still upload actual image if baseline image does not exist
            except IOError as e:
                failed = True
                if "Baseline image" in msg and "does not exist." in msg:
                    msg = str(e) + "\n"
                    upload_result = self._upload_images()
                    if isinstance(upload_result, dict):
                        msg += ("\tFile:      {}\n"
                                "\tExpected:  ---\n"
                                "\tActual:    {actual}\n"
                                "\tDiff:      ---\n").format(self.image_name,
                                                             **upload_result)
                    else:
                        msg += upload_result
                    raise ImageComparisonException(msg)
                raise
            # simply reraise on any other unhandled exceptions
            except Exception:
                failed = True
                raise
            # if image comparison not raises by itself, the test failed if we get a
            # message back or the test passed if we get an empty message
            else:
                if msg:
                    failed = True
                else:
                    failed = False
                if failed:
                    # base message on deviation of baseline and actual image
                    msg = ("Image comparison failed.\n"
                           "\tFile:      {}\n"
                           "\tRMS:       {rms}\n"
                           "\tTolerance: {tol}\n").format(self.image_name, **msg)
                    # optionally, copy failed images from /tmp and append
                    # the local paths
                    if self.keep_output:
                        ff = self._get_final_filenames()
                        msg += ("\tExpected:  {expected}\n"
                                "\tActual:    {actual}\n"
                                "\tDiff:      {diff}\n").format(**ff)
                    # try to upload to imgur, if successful append links to message
                    upload_result = self._upload_images()
                    if isinstance(upload_result, dict):
                        msg += ("\tExpected:  {expected}\n"
                                "\tActual:    {actual}\n"
                                "\tDiff:      {diff}\n").format(**upload_result)
                    else:
                        msg += upload_result
                    msg = msg.rstrip()
                    raise ImageComparisonException(msg)
            # finally clean up after the image test, whether failed or not.
            # if specified move generated output to source tree
            finally:
                self.close()  # flush internal buffer
                self._fileobj.close()
                if self.plt_close_all_exit:
                    import matplotlib.pyplot as plt
                    try:
                        plt.close("all")
                    except Exception:
                        pass
                if self.style is not None:
                    self.style.__exit__(exc_type, exc_val, exc_tb)
                if self.keep_output:
                    if failed or not self.keep_only_failed:
                        self._copy_tempfiles()
                # delete temporary files
                os.remove(self.name)
                if os.path.exists(self.diff_filename):
                    os.remove(self.diff_filename)

        def compare(self):
            """
            Run a custom version
            of :func:`matplotlib.testing.compare.compare_images` and raise an
            unittest.TestCase.failureException with the message string given by
            matplotlib if the comparison exceeds the allowed tolerance.
            """
            if os.stat(self.name).st_size == 0:
                msg = "Empty output image file."
                raise ImageComparisonException(msg)

            return compare_images(self.baseline_image, self.name, tol=self.tol)

        def _get_final_filenames(self):
            """
            Helper function returning the
            :return:
            """
            directory = self.output_path
            filename_new = os.path.join(directory, self.image_name)
            diff_filename_new = "-failed-diff.".join(
                self.image_name.rsplit(".", 1))
            diff_filename_new = os.path.join(directory, diff_filename_new)
            return {"actual": os.path.abspath(filename_new),
                    "expected": os.path.abspath(self.baseline_image),
                    "diff": os.path.abspath(diff_filename_new)}

        def _copy_tempfiles(self):
            """
            Copies created images from tempfiles to a subfolder of baseline images.
            """
            try:
                filenames = self._get_final_filenames()
                directory = self.output_path
                if os.path.exists(directory):
                    if not os.path.isdir(directory):
                        msg = ("Could not keep output image, target directory "
                               "exists but is no directory: %s") % directory
                        warnings.warn(msg)
                        return
                else:
                    os.mkdir(directory)
                if os.path.isfile(self.diff_filename):
                    shutil.copy(self.diff_filename, filenames["diff"])
                shutil.copy(self.name, filenames["actual"])
            except Exception as e:
                msg = ("Failed to copy images from temporary directory "
                       "(caught %s: %s).") % (e.__class__.__name__, str(e))
                warnings.warn(msg)

        def _upload_images(self):
            """
            Uploads images to imgur unless explicitly deactivated with option
            `no_uploads` (to speed up tests that are expected to fail).

            :returns: ``dict`` with links to uploaded images or ``str`` with
                message if upload failed
            """
            if self.no_uploads:
                return "Upload to imgur deactivated with option 'no_uploads'."
            try:
                import pyimgur
                # try to get imgur client id from environment
                imgur_clientid = \
                    os.environ.get("OBSPY_IMGUR_CLIENTID") or "53b182544dc5d89"
                imgur_client_secret = \
                    os.environ.get("OBSPY_IMGUR_CLIENT_SECRET", None)
                imgur_client_refresh_token = \
                    os.environ.get("OBSPY_IMGUR_REFRESH_TOKEN", None)
                # upload images and return urls
                links = {}
                imgur = pyimgur.Imgur(imgur_clientid,
                                      client_secret=imgur_client_secret,
                                      refresh_token=imgur_client_refresh_token)
                if imgur_client_secret and imgur_client_refresh_token:
                    try:
                        imgur.refresh_access_token()
                    except Exception as e:
                        msg = ('Refreshing access token for Imgur API failed '
                               '(caught {}: {!s}).)').format(e.__class__.__name__,
                                                             e)
                        warnings.warn(msg)
                if os.path.exists(self.baseline_image):
                    up = imgur.upload_image(self.baseline_image, title=self.name)
                    links['expected'] = up.link
                if os.path.exists(self.name):
                    up = imgur.upload_image(self.name, title=self.name)
                    links['actual'] = up.link
                if os.path.exists(self.diff_filename):
                    up = imgur.upload_image(self.diff_filename,
                                            title=self.diff_filename)
                    links['diff'] = up.link
            except Exception as e:
                msg = ("Upload to imgur failed (caught %s: %s).")
                return msg % (e.__class__.__name__, str(e))
            return links

    def compare_xml_strings(doc1, doc2):
        """
        Simple helper function to compare two XML strings.

        :type doc1: str
        :type doc2: str
        """
        # Compat py2k and py3k
        try:
            doc1 = doc1.encode()
            doc2 = doc2.encode()
        except Exception:
            pass
        obj1 = etree.fromstring(doc1).getroottree()
        obj2 = etree.fromstring(doc2).getroottree()

        buf = io.BytesIO()
        obj1.write_c14n(buf)
        buf.seek(0, 0)
        str1 = buf.read().decode()
        str1 = [_i.strip() for _i in str1.splitlines()]

        buf = io.BytesIO()
        obj2.write_c14n(buf)
        buf.seek(0, 0)
        str2 = buf.read().decode()
        str2 = [_i.strip() for _i in str2.splitlines()]

        unified_diff = difflib.unified_diff(str1, str2)

        err_msg = "\n".join(unified_diff)
        if err_msg:  # pragma: no cover
            raise AssertionError("Strings are not equal.\n" + err_msg)

    def remove_unique_ids(xml_string, remove_creation_time=False):
        """
        Removes unique ID parts of e.g. 'publicID="..."' attributes from xml
        strings.

        :type xml_string: str
        :param xml_string: xml string to process
        :type remove_creation_time: bool
        :param xml_string: controls whether to remove 'creationTime' tags or not.
        :rtype: str
        """
        prefixes = ["id", "publicID", "pickID", "originID", "preferredOriginID",
                    "preferredMagnitudeID", "preferredFocalMechanismID",
                    "referenceSystemID", "methodID", "earthModelID",
                    "triggeringOriginID", "derivedOriginID", "momentMagnitudeID",
                    "greensFunctionID", "filterID", "amplitudeID",
                    "stationMagnitudeID", "earthModelID", "slownessMethodID",
                    "pickReference", "amplitudeReference"]
        if remove_creation_time:
            prefixes.append("creationTime")
        for prefix in prefixes:
            xml_string = re.sub("%s='.*?'" % prefix, '%s=""' % prefix, xml_string)
            xml_string = re.sub('%s=".*?"' % prefix, '%s=""' % prefix, xml_string)
            xml_string = re.sub("<%s>.*?</%s>" % (prefix, prefix),
                                '<%s/>' % prefix, xml_string)
        return xml_string

    def get_all_py_files():
        """
        Return a list with full absolute paths to all .py files in ObsPy file tree.

        :rtype: list of str
        """
        util_dir = os.path.abspath(inspect.getfile(inspect.currentframe()))
        obspy_dir = os.path.dirname(os.path.dirname(os.path.dirname(util_dir)))
        py_files = set()
        # Walk the obspy directory structure
        for dirpath, _, filenames in os.walk(obspy_dir):
            py_files.update([os.path.abspath(os.path.join(dirpath, i)) for i in
                             filenames if i.endswith(".py")])
        return sorted(py_files)

    class WarningsCapture(object):
        """
        Try hard to capture all warnings.

        Aims to be a reliable drop-in replacement for built-in
        warnings.catch_warnings() context manager.

        Based on pytest's _DeprecatedCallContext context manager.
        """
        def __enter__(self):
            self.captured_warnings = []
            self._old_warn = warnings.warn
            self._old_warn_explicit = warnings.warn_explicit
            warnings.warn_explicit = self._warn_explicit
            warnings.warn = self._warn
            return self

        def _warn_explicit(self, message, category, *args, **kwargs):
            self.captured_warnings.append(
                warnings.WarningMessage(message=category(message),
                                        category=category,
                                        filename="", lineno=0))

        def _warn(self, message, category=None, *args, **kwargs):
            if isinstance(message, Warning):
                self.captured_warnings.append(
                    warnings.WarningMessage(
                        message=category(message), category=category or Warning,
                        filename="", lineno=0))
            else:
                self.captured_warnings.append(
                    warnings.WarningMessage(
                        message=category(message), category=category,
                        filename="", lineno=0))

        def __exit__(self, exc_type, exc_val, exc_tb):
            warnings.warn_explicit = self._old_warn_explicit
            warnings.warn = self._old_warn

        def __len__(self):
            return len(self.captured_warnings)

        def __getitem__(self, key):
            return self.captured_warnings[key]

    if __name__ == '__main__':
        doctest.testmod(exclude_empty=True)

### Thank you!

We would like to thank our contributors, whose efforts make this software what it is. These people have helped by writing code and documentation, and by testing. They have created and maintained this product, its associated libraries and applications, our build tools and our web sites.

#### Contributors

- Ackerley, Nick
- Allgeyer, Sebastien
- Ammon, Charles J.
- Antunes, Emanuel
- Arnarsson, Ólafur St.
- Bank, Markus
- Barsch, Robert
- Behr, Yannik
- Bernardi, Fabrizio
- Bernauer, Felix
- Bes de Berc, Maxime
- Beyreuther, Moritz
- Boltz, Shawn
- Bonaimé, Sébastien
- Carothers, Lloyd
- Chamberlain, Calum
- Chambers, Derrick
- Chen, Zhao
- Clark, Adam
- Danecek, Peter
- Egdorf, Sven
- Engels, Fabian
- Ermert, Laura
- Eulenfeld, Tom

- Fabbri, Tommaso
- Falco, Nicholas
- Fee, Jeremy
- Grellier, Clément
- Grunberg, Marc
- Hammer, Conny
- Heimann, Sebastian
- Heiniger, Lukas
- Hope, Gaute
- Igel, Heiner
- Inza, Adolfo
- Isken, Marius
- Ketchum, David
- Koymans, Mathijs
- Kremers, Simon
- Kress, Victor
- Krieger, Lars
- Krischer, Lion
- Kula, Damian
- Käufl, Paul
- Köhler, Andreas
- Lecocq, Thomas
- Leeman, John
- Legovini, Paride

- Lesage, Philippe
- Li, Yulin
- Lomax, Anthony
- Lopes, Rui L.
- MacCarthy, Jonathan
- Maggi, Alessia
- Martin, Henri
- Medlin, Andrew
- Megies, Tobias
- Meschede, Matthias
- Michelini, Alberto
- Miller, Nathaniel C.
- Morgenstern, Bernhard
- Nof, Ran Novitsky
- Panning, Mark P.
- Parker, Tom
- Pestourie, Romain
- Rapagnani, Giovanni
- Reyes, Celso
- Ringler, Adam
- Rothenhäusler, Nicolas
- Russo, Emiliano
- Sales de Andrade, Elliott

- Satriano, Claudio
- Saul, Joachim
- Scheingraber, Chris
- Schneider, Simon
- Sippl, Christian
- Snoke, Arthur
- Stange, Stefan
- Stähler, Simon C.
- Sullivan, Benjamin
- Tian, Dongdong
- Trabant, Chad
- Trani, Luca
- Uieda, Leonardo
- Walker, Andrew
- Walther, Marcus
- Wassermann, Joachim
- Williams, Mark C.
- Winkelman, Andrew
- Zaccarelli, Riccardo
- Zad, Seyed Kasra Hosseini
- Zhu, Lijun
- van Driel, Martin
- van Wijk, Kasper

#### Funds

ObsPy was partially funded by the

- German Science Foundation (DFG) via grant DFG IG 16/9-1
- German Ministry for Education and Research (BMBF), GEOTECHNOLOGIEN grant 03G0646H.
- NERA project (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation) under the European Community's Seventh Framework Programme (FP7/2007-2013) grant agreement n° 262330
- Leibniz Institute for Applied Geophysics (LIAG)
- VERCE EU-FP7 project (no. 283543)