Source code for envisage.resource.tests.test_resource_manager

# (C) Copyright 2007-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Tests for the resource manager. """


# Standard library imports.
import unittest
import urllib.request
from io import StringIO
from urllib.error import HTTPError

try:
    from importlib.resources import as_file, files
except ImportError:
    from importlib_resources import as_file, files


# Enthought library imports.
from envisage.resource.api import NoSuchResourceError, ResourceManager

# Module to patch urlopen in during testing.
url_library = urllib.request


# This module's package.
PKG = "envisage.resource.tests"


# mimics `urlopen` for some tests.
# In setUp it replaces `urlopen` for some tests,
# and in tearDown, the regular `urlopen` is put back into place.
def stubout_urlopen(url):
    if "bogus" in url:
        raise HTTPError(url, "404", "No such resource", "", None)

    elif "localhost" in url:
        return StringIO("This is a test file.\n")

    else:
        raise ValueError("Unexpected URL %r in stubout_urlopen" % url)


class ResourceManagerTestCase(unittest.TestCase):
    """Tests for the resource manager."""

    ###########################################################################
    # 'TestCase' interface.
    ###########################################################################

    def setUp(self):
        """Prepares the test fixture before each test method is called."""

        self.stored_urlopen = url_library.urlopen
        url_library.urlopen = stubout_urlopen

    def tearDown(self):
        """Called immediately after each test method has been called."""

        url_library.urlopen = self.stored_urlopen

    ###########################################################################
    # Tests.
    ###########################################################################

    def test_file_resource(self):
        """file resource"""

        rm = ResourceManager()

        # Get the filename of the 'api.py' file.
        resource = files("envisage.resource") / "api.py"
        with as_file(resource) as path:
            # Open a file resource.
            f = rm.file(f"file://{path}")
            self.assertNotEqual(f, None)
            contents = f.read()
            f.close()

            # Open the api file via the file system.
            with open(path, "rb") as g:
                self.assertEqual(g.read(), contents)

    def test_no_such_file_resource(self):
        """no such file resource"""

        rm = ResourceManager()

        # Open a file resource.
        with self.assertRaises(NoSuchResourceError):
            rm.file("file://../bogus.py")

    def test_package_resource(self):
        """package resource"""

        rm = ResourceManager()

        # Open a package resource.
        f = rm.file("pkgfile://envisage.resource/api.py")
        self.assertNotEqual(f, None)
        contents = f.read()
        f.close()

        # Get the bytes of the 'api.py' file.
        resource = files("envisage.resource") / "api.py"
        with resource.open("rb") as g:
            self.assertEqual(g.read(), contents)

    def test_package_resource_subdir(self):
        """package resource"""

        rm = ResourceManager()

        # Open a package resource.
        f = rm.file("pkgfile://envisage.resource/tests/__init__.py")
        self.assertNotEqual(f, None)
        contents = f.read()
        f.close()

        # Get the bytes of the 'api.py' file.
        resource = files("envisage.resource") / "tests" / "__init__.py"
        with resource.open("rb") as g:
            self.assertEqual(g.read(), contents)

    def test_no_such_package_resource(self):
        """no such package resource"""

        rm = ResourceManager()

        # Open a package resource.
        with self.assertRaises(NoSuchResourceError):
            rm.file("pkgfile://envisage.resource/")

        with self.assertRaises(NoSuchResourceError):
            rm.file("pkgfile:///envisage")

        with self.assertRaises(NoSuchResourceError):
            rm.file("pkgfile://envisage.resource/bogus.py")

        with self.assertRaises(NoSuchResourceError):
            rm.file("pkgfile://completely.bogus/bogus.py")

        with self.assertRaises(NoSuchResourceError):
            rm.file("pkgfile://envisage.resource.resource_manager/anything")

    def test_http_resource(self):
        """http resource"""

        # Open an HTTP document resource.
        rm = ResourceManager()

        f = rm.file("http://localhost:1234/file.dat")
        self.assertNotEqual(f, None)
        contents = f.read()
        f.close()

        self.assertEqual(contents, "This is a test file.\n")

    def test_no_such_http_resource(self):
        """no such http resource"""

        # Open an HTTP document resource.
        rm = ResourceManager()

        with self.assertRaises(NoSuchResourceError):
            rm.file("http://localhost:1234/bogus.dat")

    def test_unknown_protocol(self):
        """unknown protocol"""

        # Open an HTTP document resource.
        rm = ResourceManager()

        with self.assertRaises(ValueError):
            rm.file("bogus://foo/bar/baz")