1 files changed, 33 insertions, 28 deletions

diff --git a/tests/unit/test_commands.py b/tests/unit/test_commands.py
index cb144c5f6..7a5c4e831 100644
--- a/tests/unit/test_commands.py
+++ b/tests/unit/test_commands.py
@@ -1,7 +1,9 @@
-from unittest.mock import patch
+from typing import Callable, List
+from unittest import mock
 
 import pytest
 
+from pip._internal.cli.base_command import Command
 from pip._internal.cli.req_command import (
     IndexGroupCommand,
     RequirementCommand,
@@ -11,71 +13,70 @@ from pip._internal.commands import commands_dict, create_command
 
 # These are the expected names of the commands whose classes inherit from
 # IndexGroupCommand.
-EXPECTED_INDEX_GROUP_COMMANDS = [
-    'download', 'index', 'install', 'list', 'wheel']
+EXPECTED_INDEX_GROUP_COMMANDS = ["download", "index", "install", "list", "wheel"]
 
 
-def check_commands(pred, expected):
+def check_commands(pred: Callable[[Command], bool], expected: List[str]) -> None:
     """
     Check the commands satisfying a predicate.
     """
     commands = [create_command(name) for name in sorted(commands_dict)]
     actual = [command.name for command in commands if pred(command)]
-    assert actual == expected, f'actual: {actual}'
+    assert actual == expected, f"actual: {actual}"
 
 
-def test_commands_dict__order():
+def test_commands_dict__order() -> None:
     """
     Check the ordering of commands_dict.
     """
     names = list(commands_dict)
     # A spot-check is sufficient to check that commands_dict encodes an
     # ordering.
-    assert names[0] == 'install'
-    assert names[-1] == 'help'
+    assert names[0] == "install"
+    assert names[-1] == "help"
 
 
-@pytest.mark.parametrize('name', list(commands_dict))
-def test_create_command(name):
+@pytest.mark.parametrize("name", list(commands_dict))
+def test_create_command(name: str) -> None:
     """Test creating an instance of each available command."""
     command = create_command(name)
     assert command.name == name
     assert command.summary == commands_dict[name].summary
 
 
-def test_session_commands():
+def test_session_commands() -> None:
     """
     Test which commands inherit from SessionCommandMixin.
     """
-    def is_session_command(command):
+
+    def is_session_command(command: Command) -> bool:
         return isinstance(command, SessionCommandMixin)
 
-    expected = [
-        'download', 'index', 'install', 'list', 'search', 'uninstall', 'wheel'
-    ]
+    expected = ["download", "index", "install", "list", "search", "uninstall", "wheel"]
     check_commands(is_session_command, expected)
 
 
-def test_index_group_commands():
+def test_index_group_commands() -> None:
     """
     Test the commands inheriting from IndexGroupCommand.
     """
-    def is_index_group_command(command):
+
+    def is_index_group_command(command: Command) -> bool:
         return isinstance(command, IndexGroupCommand)
 
     check_commands(is_index_group_command, EXPECTED_INDEX_GROUP_COMMANDS)
 
     # Also check that the commands inheriting from IndexGroupCommand are
     # exactly the commands with the --no-index option.
-    def has_option_no_index(command):
-        return command.parser.has_option('--no-index')
+    def has_option_no_index(command: Command) -> bool:
+        return command.parser.has_option("--no-index")
 
     check_commands(has_option_no_index, EXPECTED_INDEX_GROUP_COMMANDS)
 
 
-@pytest.mark.parametrize('command_name', EXPECTED_INDEX_GROUP_COMMANDS)
+@pytest.mark.parametrize("command_name", EXPECTED_INDEX_GROUP_COMMANDS)
 @pytest.mark.parametrize(
-    'disable_pip_version_check, no_index, expected_called',
+    "disable_pip_version_check, no_index, expected_called",
     [
         # pip_self_version_check() is only called when both
         # disable_pip_version_check and no_index are False.
@@ -85,11 +86,14 @@ def test_index_group_commands():
         (True, True, False),
     ],
 )
-@patch('pip._internal.cli.req_command.pip_self_version_check')
+@mock.patch("pip._internal.cli.req_command.pip_self_version_check")
 def test_index_group_handle_pip_version_check(
-    mock_version_check, command_name, disable_pip_version_check, no_index,
-    expected_called,
-):
+    mock_version_check: mock.Mock,
+    command_name: str,
+    disable_pip_version_check: bool,
+    no_index: bool,
+    expected_called: bool,
+) -> None:
     """
     Test whether pip_self_version_check() is called when
     handle_pip_version_check() is called, for each of the
@@ -107,11 +111,12 @@ def test_index_group_handle_pip_version_check(
         mock_version_check.assert_not_called()
 
 
-def test_requirement_commands():
+def test_requirement_commands() -> None:
     """
     Test which commands inherit from RequirementCommand.
     """
-    def is_requirement_command(command):
+
+    def is_requirement_command(command: Command) -> bool:
         return isinstance(command, RequirementCommand)
 
-    check_commands(is_requirement_command, ['download', 'install', 'wheel'])
+    check_commands(is_requirement_command, ["download", "install", "wheel"])