diff --git a/pip/download.py b/pip/download.py
index 000f4594a..281118b50 100644
--- a/pip/download.py
+++ b/pip/download.py
@@ -213,7 +213,9 @@ def get_file_content(url, comes_from=None, session=None):
     """Gets the content of a file; it may be a filename, file: URL, or
     http: URL.  Returns (location, content).  Content is unicode."""
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "get_file_content() missing 1 required keyword argument: 'session'"
+        )
 
     match = _scheme_re.search(url)
     if match:
@@ -494,7 +496,9 @@ def _copy_file(filename, location, content_type, link):
 def unpack_http_url(link, location, download_cache, download_dir=None,
                     session=None):
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "unpack_http_url() missing 1 required keyword argument: 'session'"
+        )
 
     temp_dir = tempfile.mkdtemp('-unpack', 'pip-')
     temp_location = None
diff --git a/pip/index.py b/pip/index.py
index 295246a7d..58c1a299e 100644
--- a/pip/index.py
+++ b/pip/index.py
@@ -13,7 +13,7 @@ from pip.exceptions import (
     UnsupportedWheel,
 )
 from pip.backwardcompat import urlparse, url2pathname
-from pip.download import PipSession, url_to_path, path_to_url
+from pip.download import url_to_path, path_to_url
 from pip.wheel import Wheel, wheel_ext
 from pip.pep425tags import supported_tags, supported_tags_noarch, get_platform
 from pip._vendor import html5lib, requests, pkg_resources
@@ -39,6 +39,12 @@ class PackageFinder(object):
                  use_wheel=True, allow_external=[], allow_unverified=[],
                  allow_all_external=False, allow_all_prereleases=False,
                  session=None):
+        if session is None:
+            raise TypeError(
+                "PackageFinder() missing 1 required keyword argument: "
+                "'session'"
+            )
+
         self.find_links = find_links
         self.index_urls = index_urls
         self.cache = PageCache()
@@ -73,7 +79,7 @@ class PackageFinder(object):
         self.allow_all_prereleases = allow_all_prereleases
 
         # The Session we'll use to make requests
-        self.session = session or PipSession()
+        self.session = session
 
     def _sort_locations(self, locations):
         """
@@ -717,7 +723,9 @@ class HTMLPage(object):
     @classmethod
     def get_page(cls, link, req, cache=None, skip_archives=True, session=None):
         if session is None:
-            session = PipSession()
+            raise TypeError(
+                "get_page() missing 1 required keyword argument: 'session'"
+            )
 
         url = link.url
         url = url.split('#', 1)[0]
@@ -827,11 +835,8 @@ class HTMLPage(object):
             cache.add_page_failure(url, level)
 
     @staticmethod
-    def _get_content_type(url, session=None):
+    def _get_content_type(url, session):
         """Get the Content-Type of the given url, using a HEAD request"""
-        if session is None:
-            session = PipSession()
-
         scheme, netloc, path, query, fragment = urlparse.urlsplit(url)
         if scheme not in ('http', 'https', 'ftp', 'ftps'):
             # FIXME: some warning or something?
diff --git a/pip/req/req_file.py b/pip/req/req_file.py
index a572e2c60..1dd5e6f73 100644
--- a/pip/req/req_file.py
+++ b/pip/req/req_file.py
@@ -2,7 +2,7 @@ import os
 import re
 
 from pip.backwardcompat import urlparse
-from pip.download import PipSession, get_file_content
+from pip.download import get_file_content
 from pip.req.req_install import InstallRequirement
 from pip.util import normalize_name
 
@@ -12,7 +12,10 @@ _scheme_re = re.compile(r'^(http|https|file):', re.I)
 def parse_requirements(filename, finder=None, comes_from=None, options=None,
                        session=None):
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "parse_requirements() missing 1 required keyword argument: "
+            "'session'"
+        )
 
     skip_match = None
     skip_regex = options.skip_requirements_regex if options else None
diff --git a/pip/req/req_set.py b/pip/req/req_set.py
index 11291be90..ac55c8659 100644
--- a/pip/req/req_set.py
+++ b/pip/req/req_set.py
@@ -4,7 +4,7 @@ import zipfile
 
 from pip._vendor import pkg_resources
 from pip.backwardcompat import HTTPError
-from pip.download import (PipSession, url_to_path, unpack_vcs_link, is_vcs_url,
+from pip.download import (url_to_path, unpack_vcs_link, is_vcs_url,
                           is_file_url, unpack_file_url, unpack_http_url)
 from pip.exceptions import (InstallationError, BestVersionAlreadyInstalled,
                             DistributionNotFound, PreviousBuildDirError)
@@ -54,6 +54,12 @@ class RequirementSet(object):
                  target_dir=None, ignore_dependencies=False,
                  force_reinstall=False, use_user_site=False, session=None,
                  pycompile=True, wheel_download_dir=None):
+        if session is None:
+            raise TypeError(
+                "RequirementSet() missing 1 required keyword argument: "
+                "'session'"
+            )
+
         self.build_dir = build_dir
         self.src_dir = src_dir
         self.download_dir = download_dir
@@ -74,7 +80,7 @@ class RequirementSet(object):
         self.as_egg = as_egg
         self.use_user_site = use_user_site
         self.target_dir = target_dir  # set from --target option
-        self.session = session or PipSession()
+        self.session = session
         self.pycompile = pycompile
         self.wheel_download_dir = wheel_download_dir
 
diff --git a/tests/unit/test_finder.py b/tests/unit/test_finder.py
index b5a628954..bb3653cf0 100644
--- a/tests/unit/test_finder.py
+++ b/tests/unit/test_finder.py
@@ -11,13 +11,14 @@ from pip.exceptions import (
     BestVersionAlreadyInstalled, DistributionNotFound, InstallationError,
 )
 from pip.util import Inf
+from pip.download import PipSession
 
 from mock import Mock, patch
 
 
 def test_no_mpkg(data):
     """Finder skips zipfiles with "macosx10" in the name."""
-    finder = PackageFinder([data.find_links], [])
+    finder = PackageFinder([data.find_links], [], session=PipSession())
     req = InstallRequirement.from_line("pkgwithmpkg")
     found = finder.find_requirement(req, False)
 
@@ -26,7 +27,7 @@ def test_no_mpkg(data):
 
 def test_no_partial_name_match(data):
     """Finder requires the full project name to match, not just beginning."""
-    finder = PackageFinder([data.find_links], [])
+    finder = PackageFinder([data.find_links], [], session=PipSession())
     req = InstallRequirement.from_line("gmpy")
     found = finder.find_requirement(req, False)
 
@@ -36,7 +37,11 @@ def test_no_partial_name_match(data):
 def test_duplicates_sort_ok(data):
     """Finder successfully finds one of a set of duplicates in different
     locations"""
-    finder = PackageFinder([data.find_links, data.find_links2], [])
+    finder = PackageFinder(
+        [data.find_links, data.find_links2],
+        [],
+        session=PipSession(),
+    )
     req = InstallRequirement.from_line("duplicate")
     found = finder.find_requirement(req, False)
 
@@ -46,7 +51,7 @@ def test_duplicates_sort_ok(data):
 def test_finder_detects_latest_find_links(data):
     """Test PackageFinder detects latest using find-links"""
     req = InstallRequirement.from_line('simple', None)
-    finder = PackageFinder([data.find_links], [])
+    finder = PackageFinder([data.find_links], [], session=PipSession())
     link = finder.find_requirement(req, False)
     assert link.url.endswith("simple-3.0.tar.gz")
 
@@ -62,7 +67,7 @@ def test_finder_detects_latest_already_satisfied_find_links(data):
         version=latest_version
     )
     req.satisfied_by = satisfied_by
-    finder = PackageFinder([data.find_links], [])
+    finder = PackageFinder([data.find_links], [], session=PipSession())
 
     with pytest.raises(BestVersionAlreadyInstalled):
         finder.find_requirement(req, True)
@@ -79,7 +84,11 @@ def test_finder_detects_latest_already_satisfied_pypi_links():
         version=latest_version,
     )
     req.satisfied_by = satisfied_by
-    finder = PackageFinder([], ["http://pypi.python.org/simple"])
+    finder = PackageFinder(
+        [],
+        ["http://pypi.python.org/simple"],
+        session=PipSession(),
+    )
 
     with pytest.raises(BestVersionAlreadyInstalled):
         finder.find_requirement(req, True)
@@ -98,7 +107,12 @@ class TestWheel:
         logger.add_consumers((logger.DEBUG, log.append))
         req = InstallRequirement.from_line("invalid")
         # data.find_links contains "invalid.whl", which is an invalid wheel
-        finder = PackageFinder([data.find_links], [], use_wheel=True)
+        finder = PackageFinder(
+            [data.find_links],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
         with pytest.raises(DistributionNotFound):
             finder.find_requirement(req, True)
         "invalid.whl because the wheel filename is invalid" in "".join(log)
@@ -114,7 +128,12 @@ class TestWheel:
         )
 
         req = InstallRequirement.from_line("simple.dist")
-        finder = PackageFinder([data.find_links], [], use_wheel=True)
+        finder = PackageFinder(
+            [data.find_links],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
 
         with pytest.raises(DistributionNotFound):
             finder.find_requirement(req, True)
@@ -130,7 +149,12 @@ class TestWheel:
         )
 
         req = InstallRequirement.from_line("simple.dist")
-        finder = PackageFinder([data.find_links], [], use_wheel=True)
+        finder = PackageFinder(
+            [data.find_links],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
         found = finder.find_requirement(req, True)
         assert (
             found.url.endswith("simple.dist-0.1-py2.py3-none-any.whl"), found
@@ -142,7 +166,12 @@ class TestWheel:
         `test_link_sorting` also covers this at lower level
         """
         req = InstallRequirement.from_line("priority")
-        finder = PackageFinder([data.find_links], [], use_wheel=True)
+        finder = PackageFinder(
+            [data.find_links],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
         found = finder.find_requirement(req, True)
         assert found.url.endswith("priority-1.0-py2.py3-none-any.whl"), found
 
@@ -159,7 +188,12 @@ class TestWheel:
             version=latest_version,
         )
         req.satisfied_by = satisfied_by
-        finder = PackageFinder([data.find_links], [], use_wheel=True)
+        finder = PackageFinder(
+            [data.find_links],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
 
         with pytest.raises(BestVersionAlreadyInstalled):
             finder.find_requirement(req, True)
@@ -186,7 +220,7 @@ class TestWheel:
             (parse_version('1.0'), Link('simple-1.0.tar.gz'), '1.0'),
         ]
 
-        finder = PackageFinder([], [])
+        finder = PackageFinder([], [], session=PipSession())
         finder.use_wheel = True
 
         results = finder._sort_versions(links)
@@ -203,7 +237,7 @@ class TestWheel:
                 '1.0',
             ),
         ]
-        finder = PackageFinder([], [], use_wheel=True)
+        finder = PackageFinder([], [], use_wheel=True, session=PipSession())
         with pytest.raises(InstallationError):
             finder._sort_versions(links)
 
@@ -214,6 +248,7 @@ def test_finder_priority_file_over_page(data):
     finder = PackageFinder(
         [data.find_links],
         ["http://pypi.python.org/simple"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.url.startswith("file://")
@@ -224,7 +259,7 @@ def test_finder_priority_nonegg_over_eggfragments():
     req = InstallRequirement.from_line('bar==1.0', None)
     links = ['http://foo/bar.py#egg=bar-1.0', 'http://foo/bar-1.0.tar.gz']
 
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
@@ -232,7 +267,7 @@ def test_finder_priority_nonegg_over_eggfragments():
     assert link.url.endswith('tar.gz')
 
     links.reverse()
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
@@ -248,20 +283,20 @@ def test_finder_only_installs_stable_releases(data):
     req = InstallRequirement.from_line("bar", None)
 
     # using a local index (that has pre & dev releases)
-    finder = PackageFinder([], [data.index_url("pre")])
+    finder = PackageFinder([], [data.index_url("pre")], session=PipSession())
     link = finder.find_requirement(req, False)
     assert link.url.endswith("bar-1.0.tar.gz"), link.url
 
     # using find-links
     links = ["https://foo/bar-1.0.tar.gz", "https://foo/bar-2.0b1.tar.gz"]
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
         assert link.url == "https://foo/bar-1.0.tar.gz"
 
     links.reverse()
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
@@ -276,20 +311,20 @@ def test_finder_installs_pre_releases(data):
     req = InstallRequirement.from_line("bar", None, prereleases=True)
 
     # using a local index (that has pre & dev releases)
-    finder = PackageFinder([], [data.index_url("pre")])
+    finder = PackageFinder([], [data.index_url("pre")], session=PipSession())
     link = finder.find_requirement(req, False)
     assert link.url.endswith("bar-2.0b1.tar.gz"), link.url
 
     # using find-links
     links = ["https://foo/bar-1.0.tar.gz", "https://foo/bar-2.0b1.tar.gz"]
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
         assert link.url == "https://foo/bar-2.0b1.tar.gz"
 
     links.reverse()
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
@@ -304,7 +339,7 @@ def test_finder_installs_dev_releases(data):
     req = InstallRequirement.from_line("bar", None, prereleases=True)
 
     # using a local index (that has dev releases)
-    finder = PackageFinder([], [data.index_url("dev")])
+    finder = PackageFinder([], [data.index_url("dev")], session=PipSession())
     link = finder.find_requirement(req, False)
     assert link.url.endswith("bar-2.0.dev1.tar.gz"), link.url
 
@@ -316,14 +351,14 @@ def test_finder_installs_pre_releases_with_version_spec():
     req = InstallRequirement.from_line("bar>=0.0.dev0", None)
     links = ["https://foo/bar-1.0.tar.gz", "https://foo/bar-2.0b1.tar.gz"]
 
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
         assert link.url == "https://foo/bar-2.0b1.tar.gz"
 
     links.reverse()
-    finder = PackageFinder(links, [])
+    finder = PackageFinder(links, [], session=PipSession())
 
     with patch.object(finder, "_get_pages", lambda x, y: []):
         link = finder.find_requirement(req, False)
@@ -337,7 +372,11 @@ def test_finder_ignores_external_links(data):
     req = InstallRequirement.from_line("bar", None)
 
     # using a local index
-    finder = PackageFinder([], [data.index_url("externals")])
+    finder = PackageFinder(
+        [],
+        [data.index_url("externals")],
+        session=PipSession(),
+    )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-1.0.tar.gz"
 
@@ -354,6 +393,7 @@ def test_finder_finds_external_links_with_hashes_per_project(data):
         [],
         [data.index_url("externals")],
         allow_external=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-2.0.tar.gz"
@@ -371,6 +411,7 @@ def test_finder_finds_external_links_with_hashes_all(data):
         [],
         [data.index_url("externals")],
         allow_all_external=True,
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-2.0.tar.gz"
@@ -388,6 +429,7 @@ def test_finder_finds_external_links_without_hashes_per_project(data):
         [data.index_url("externals")],
         allow_external=["bar"],
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-3.0.tar.gz"
@@ -406,6 +448,7 @@ def test_finder_finds_external_links_without_hashes_all(data):
         [data.index_url("externals")],
         allow_all_external=True,
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-3.0.tar.gz"
@@ -423,6 +466,7 @@ def test_finder_finds_external_links_without_hashes_scraped_per_project(data):
         [data.index_url("externals")],
         allow_external=["bar"],
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-4.0.tar.gz"
@@ -441,6 +485,7 @@ def test_finder_finds_external_links_without_hashes_scraped_all(data):
         [data.index_url("externals")],
         allow_all_external=True,
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-4.0.tar.gz"
@@ -459,6 +504,7 @@ def test_finder_finds_external_links_without_hashes_per_project_all_insecure(
         [data.index_url("externals")],
         allow_external=["bar"],
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-3.0.tar.gz"
@@ -477,6 +523,7 @@ def test_finder_finds_external_links_without_hashes_all_all_insecure(data):
         [data.index_url("externals")],
         allow_all_external=True,
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-3.0.tar.gz"
@@ -494,6 +541,7 @@ def test_finder_finds_external_links_without_hashes_scraped_per_project_all_inse
         [data.index_url("externals")],
         allow_external=["bar"],
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-4.0.tar.gz"
@@ -513,6 +561,7 @@ def test_finder_finds_external_links_without_hashes_scraped_all_all_insecure(
         [data.index_url("externals")],
         allow_all_external=True,
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-4.0.tar.gz"
@@ -530,6 +579,7 @@ def test_finder_finds_external_links_without_hashes_scraped_insecure(data):
         [],
         [data.index_url("externals")],
         allow_unverified=["bar"],
+        session=PipSession(),
     )
     link = finder.find_requirement(req, False)
     assert link.filename == "bar-4.0.tar.gz"
@@ -546,7 +596,12 @@ class test_link_package_versions(object):
         self.version = '1.0'
         self.parsed_version = parse_version(self.version)
         self.search_name = 'pytest'
-        self.finder = PackageFinder([], [], use_wheel=True)
+        self.finder = PackageFinder(
+            [],
+            [],
+            use_wheel=True,
+            session=PipSession(),
+        )
 
     def test_link_package_versions_match_wheel(self):
         """Test that 'pytest' archives match for 'pytest'"""
diff --git a/tests/unit/test_index.py b/tests/unit/test_index.py
index a775299f9..ef4b8b8eb 100644
--- a/tests/unit/test_index.py
+++ b/tests/unit/test_index.py
@@ -1,3 +1,4 @@
+from pip.download import PipSession
 from pip.index import package_to_requirement, HTMLPage
 from pip.index import PackageFinder, Link, INSTALLED_VERSION
 
@@ -36,7 +37,7 @@ def test_sort_locations_file_find_link(data):
     """
     Test that a file:// find-link dir gets listdir run
     """
-    finder = PackageFinder([data.find_links], [])
+    finder = PackageFinder([data.find_links], [], session=PipSession())
     files, urls = finder._sort_locations([data.find_links])
     assert files and not urls, (
         "files and not urls should have been found at find-links url: %s" %
@@ -49,7 +50,7 @@ def test_sort_locations_file_not_find_link(data):
     Test that a file:// url dir that's not a find-link, doesn't get a listdir
     run
     """
-    finder = PackageFinder([], [])
+    finder = PackageFinder([], [], session=PipSession())
     files, urls = finder._sort_locations(data.index_url("empty_with_pkg"))
     assert urls and not files, "urls, but not files should have been found"
 
diff --git a/tests/unit/test_req.py b/tests/unit/test_req.py
index cba3abd70..1b6dd077e 100644
--- a/tests/unit/test_req.py
+++ b/tests/unit/test_req.py
@@ -8,6 +8,7 @@ from mock import Mock, patch, mock_open
 from pip.exceptions import (
     PreviousBuildDirError, InvalidWheelFilename, UnsupportedWheel,
 )
+from pip.download import PipSession
 from pip.index import PackageFinder
 from pip.log import logger
 from pip.req import (InstallRequirement, RequirementSet,
@@ -34,6 +35,7 @@ class TestRequirementSet(object):
             src_dir=os.path.join(self.tempdir, 'src'),
             download_dir=None,
             download_cache=os.path.join(self.tempdir, 'download_cache'),
+            session=PipSession(),
         )
 
     def test_no_reuse_existing_build_dir(self, data):
@@ -45,7 +47,7 @@ class TestRequirementSet(object):
         reqset = self.basic_reqset()
         req = InstallRequirement.from_line('simple')
         reqset.add_requirement(req)
-        finder = PackageFinder([data.find_links], [])
+        finder = PackageFinder([data.find_links], [], session=PipSession())
         assert_raises_regexp(
             PreviousBuildDirError,
             "pip can't proceed with [\s\S]*%s[\s\S]*%s" %
@@ -181,7 +183,7 @@ def test_remote_reqs_parse():
     # previously this has failed in py3: https://github.com/pypa/pip/issues/760
     for req in parse_requirements(
             'https://raw.githubusercontent.com/pypa/pip-test-package/master/'
-            'tests/req_just_comment.txt'):
+            'tests/req_just_comment.txt', session=PipSession()):
         pass
 
 
@@ -189,9 +191,10 @@ def test_req_file_parse_use_wheel(data):
     """
     Test parsing --use-wheel from a req file
     """
-    finder = PackageFinder([], [])
+    finder = PackageFinder([], [], session=PipSession())
     for req in parse_requirements(
-            data.reqfiles.join("supported_options.txt"), finder):
+            data.reqfiles.join("supported_options.txt"), finder,
+            session=PipSession()):
         pass
     assert finder.use_wheel
 
@@ -203,8 +206,9 @@ def test_req_file_parse_comment_start_of_line(tmpdir):
     with open(tmpdir.join("req1.txt"), "w") as fp:
         fp.write("# Comment ")
 
-    finder = PackageFinder([], [])
-    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder))
+    finder = PackageFinder([], [], session=PipSession())
+    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder,
+                session=PipSession()))
 
     assert not reqs
 
@@ -216,8 +220,9 @@ def test_req_file_parse_comment_end_of_line_with_url(tmpdir):
     with open(tmpdir.join("req1.txt"), "w") as fp:
         fp.write("https://example.com/foo.tar.gz # Comment ")
 
-    finder = PackageFinder([], [])
-    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder))
+    finder = PackageFinder([], [], session=PipSession())
+    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder,
+                session=PipSession()))
 
     assert len(reqs) == 1
     assert reqs[0].url == "https://example.com/foo.tar.gz"
@@ -230,8 +235,9 @@ def test_req_file_parse_egginfo_end_of_line_with_url(tmpdir):
     with open(tmpdir.join("req1.txt"), "w") as fp:
         fp.write("https://example.com/foo.tar.gz#egg=wat")
 
-    finder = PackageFinder([], [])
-    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder))
+    finder = PackageFinder([], [], session=PipSession())
+    reqs = list(parse_requirements(tmpdir.join("req1.txt"), finder,
+                session=PipSession()))
 
     assert len(reqs) == 1
     assert reqs[0].name == "wat"