Separate pip list command from operation

pip/commands/list.py

@@ -1,15 +1,11 @@
 from __future__ import absolute_import
 
 import logging
-import warnings
 
 from pip.basecommand import Command
-from pip.exceptions import DistributionNotFound
-from pip.index import PackageFinder
-from pip.req import InstallRequirement
 from pip.utils import get_installed_distributions, dist_is_editable
-from pip.utils.deprecation import RemovedInPip7Warning
 from pip.cmdoptions import make_option_group, index_group
+from pip.operations.list import find_packages_latests_versions
 
 
 logger = logging.getLogger(__name__)
@@ -73,22 +69,6 @@ def __init__(self, *args, **kw):
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, cmd_opts)
 
-    def _build_package_finder(self, options, index_urls, session):
-        """
-        Create a package finder appropriate to this list command.
-        """
-        return PackageFinder(
-            find_links=options.find_links,
-            index_urls=index_urls,
-            allow_external=options.allow_external,
-            allow_unverified=options.allow_unverified,
-            allow_all_external=options.allow_all_external,
-            allow_all_prereleases=options.pre,
-            trusted_hosts=options.trusted_hosts,
-            process_dependency_links=options.process_dependency_links,
-            session=session,
-        )
-
     def run(self, options, args):
         if options.outdated:
             self.run_outdated(options)
@@ -108,63 +88,7 @@ def run_outdated(self, options):
                 )
 
     def find_packages_latests_versions(self, options):
-        index_urls = [options.index_url] + options.extra_index_urls
-        if options.no_index:
-            logger.info('Ignoring indexes: %s', ','.join(index_urls))
-            index_urls = []
-
-        if options.use_mirrors:
-            warnings.warn(
-                "--use-mirrors has been deprecated and will be removed in the "
-                "future. Explicit uses of --index-url and/or --extra-index-url"
-                " is suggested.",
-                RemovedInPip7Warning,
-            )
-
-        if options.mirrors:
-            warnings.warn(
-                "--mirrors has been deprecated and will be removed in the "
-                "future. Explicit uses of --index-url and/or --extra-index-url"
-                " is suggested.",
-                RemovedInPip7Warning,
-            )
-            index_urls += options.mirrors
-
-        dependency_links = []
-        for dist in get_installed_distributions(local_only=options.local,
-                                                user_only=options.user):
-            if dist.has_metadata('dependency_links.txt'):
-                dependency_links.extend(
-                    dist.get_metadata_lines('dependency_links.txt'),
-                )
-
-        with self._build_session(options) as session:
-            finder = self._build_package_finder(options, index_urls, session)
-            finder.add_dependency_links(dependency_links)
-
-            installed_packages = get_installed_distributions(
-                local_only=options.local,
-                user_only=options.user,
-                include_editables=False,
-            )
-            for dist in installed_packages:
-                req = InstallRequirement.from_line(
-                    dist.key, None, isolated=options.isolated_mode,
-                )
-                try:
-                    link = finder.find_requirement(req, True)
-
-                    # If link is None, means installed version is most
-                    # up-to-date
-                    if link is None:
-                        continue
-                except DistributionNotFound:
-                    continue
-                else:
-                    remote_version = finder._link_package_versions(
-                        link, req.name
-                    ).version
-                yield dist, remote_version
+        return find_packages_latests_versions(options, self._build_session)
 
     def run_listing(self, options):
         installed_packages = get_installed_distributions(

pip/operations/list.py

@@ -0,0 +1,88 @@
+import logging
+import warnings
+
+from pip.exceptions import DistributionNotFound
+from pip.index import PackageFinder
+from pip.req import InstallRequirement
+from pip.utils import get_installed_distributions
+from pip.utils.deprecation import RemovedInPip7Warning
+
+
+logger = logging.getLogger(__name__)
+
+
+def find_packages_latests_versions(options, build_session_func):
+    index_urls = [options.index_url] + options.extra_index_urls
+    if options.no_index:
+        logger.info('Ignoring indexes: %s', ','.join(index_urls))
+        index_urls = []
+
+    if options.use_mirrors:
+        warnings.warn(
+            "--use-mirrors has been deprecated and will be removed in the "
+            "future. Explicit uses of --index-url and/or --extra-index-url"
+            " is suggested.",
+            RemovedInPip7Warning,
+        )
+
+    if options.mirrors:
+        warnings.warn(
+            "--mirrors has been deprecated and will be removed in the "
+            "future. Explicit uses of --index-url and/or --extra-index-url"
+            " is suggested.",
+            RemovedInPip7Warning,
+        )
+        index_urls += options.mirrors
+
+    dependency_links = []
+    for dist in get_installed_distributions(local_only=options.local,
+                                            user_only=options.user):
+        if dist.has_metadata('dependency_links.txt'):
+            dependency_links.extend(
+                dist.get_metadata_lines('dependency_links.txt'),
+            )
+
+    with build_session_func(options) as session:
+        finder = _build_package_finder(options, index_urls, session)
+        finder.add_dependency_links(dependency_links)
+
+        installed_packages = get_installed_distributions(
+            local_only=options.local,
+            user_only=options.user,
+            include_editables=False,
+        )
+        for dist in installed_packages:
+            req = InstallRequirement.from_line(
+                dist.key, None, isolated=options.isolated_mode,
+            )
+            try:
+                link = finder.find_requirement(req, True)
+
+                # If link is None, means installed version is most
+                # up-to-date
+                if link is None:
+                    continue
+            except DistributionNotFound:
+                continue
+            else:
+                remote_version = finder._link_package_versions(
+                    link, req.name
+                ).version
+            yield dist, remote_version
+
+
+def _build_package_finder(options, index_urls, session):
+    """
+    Create a package finder appropriate to this list command.
+    """
+    return PackageFinder(
+        find_links=options.find_links,
+        index_urls=index_urls,
+        allow_external=options.allow_external,
+        allow_unverified=options.allow_unverified,
+        allow_all_external=options.allow_all_external,
+        allow_all_prereleases=options.pre,
+        trusted_hosts=options.trusted_hosts,
+        process_dependency_links=options.process_dependency_links,
+        session=session,
+    )