Avoid importing things from conftest

It is generally discouraged to import from conftest. Things are now
moved to tests.lib and imported from there instead.

Also did some cleanup to remove the no-longer-needed nullcontext shim.

tests/conftest.py

@@ -1,23 +1,21 @@
 import compileall
+import contextlib
 import fnmatch
-import io
 import os
 import re
 import shutil
 import subprocess
 import sys
-from contextlib import ExitStack, contextmanager
 from pathlib import Path
 from typing import (
-    TYPE_CHECKING,
     AnyStr,
     Callable,
+    ContextManager,
     Dict,
     Iterable,
     Iterator,
     List,
     Optional,
-    Union,
 )
 from unittest.mock import patch
 from zipfile import ZipFile
@@ -36,25 +34,20 @@ from installer.destinations import SchemeDictionaryDestination
 from installer.sources import WheelFile
 
 from pip import __file__ as pip_location
-from pip._internal.cli.main import main as pip_entry_point
 from pip._internal.locations import _USE_SYSCONFIG
 from pip._internal.utils.temp_dir import global_tempdir_manager
-from tests.lib import DATA_DIR, SRC_DIR, PipTestEnvironment, TestData
-from tests.lib.server import MockServer as _MockServer
-from tests.lib.server import make_mock_server, server_running
+from tests.lib import (
+    DATA_DIR,
+    SRC_DIR,
+    CertFactory,
+    InMemoryPip,
+    PipTestEnvironment,
+    ScriptFactory,
+    TestData,
+)
+from tests.lib.server import MockServer, make_mock_server
 from tests.lib.venv import VirtualEnvironment, VirtualEnvironmentType
 
-from .lib.compat import nullcontext
-
-if TYPE_CHECKING:
-    from typing import Protocol
-
-    from wsgi import WSGIApplication
-else:
-    # TODO: Protocol was introduced in Python 3.8. Remove this branch when
-    # dropping support for Python 3.7.
-    Protocol = object
-
 
 def pytest_addoption(parser: Parser) -> None:
     parser.addoption(
@@ -325,7 +318,7 @@ def scoped_global_tempdir_manager(request: pytest.FixtureRequest) -> Iterator[No
     temporary directories in the application.
     """
     if "no_auto_tempdir_manager" in request.keywords:
-        ctx = nullcontext
+        ctx: Callable[[], ContextManager[None]] = contextlib.nullcontext
     else:
         ctx = global_tempdir_manager
 
@@ -502,16 +495,6 @@ def virtualenv(
     yield virtualenv_factory(tmpdir.joinpath("workspace", "venv"))
 
 
-class ScriptFactory(Protocol):
-    def __call__(
-        self,
-        tmpdir: Path,
-        virtualenv: Optional[VirtualEnvironment] = None,
-        environ: Optional[Dict[AnyStr, AnyStr]] = None,
-    ) -> PipTestEnvironment:
-        ...
-
-
 @pytest.fixture(scope="session")
 def script_factory(
     virtualenv_factory: Callable[[Path], VirtualEnvironment],
@@ -631,26 +614,6 @@ def data(tmpdir: Path) -> TestData:
     return TestData.copy(tmpdir.joinpath("data"))
 
 
-class InMemoryPipResult:
-    def __init__(self, returncode: int, stdout: str) -> None:
-        self.returncode = returncode
-        self.stdout = stdout
-
-
-class InMemoryPip:
-    def pip(self, *args: Union[str, Path]) -> InMemoryPipResult:
-        orig_stdout = sys.stdout
-        stdout = io.StringIO()
-        sys.stdout = stdout
-        try:
-            returncode = pip_entry_point([os.fspath(a) for a in args])
-        except SystemExit as e:
-            returncode = e.code or 0
-        finally:
-            sys.stdout = orig_stdout
-        return InMemoryPipResult(returncode, stdout.getvalue())
-
-
 @pytest.fixture
 def in_memory_pip() -> InMemoryPip:
     return InMemoryPip()
@@ -662,9 +625,6 @@ def deprecated_python() -> bool:
     return sys.version_info[:2] in []
 
 
-CertFactory = Callable[[], str]
-
-
 @pytest.fixture(scope="session")
 def cert_factory(tmpdir_factory: pytest.TempPathFactory) -> CertFactory:
     # Delay the import requiring cryptography in order to make it possible
@@ -686,49 +646,6 @@ def cert_factory(tmpdir_factory: pytest.TempPathFactory) -> CertFactory:
     return factory
 
 
-class MockServer:
-    def __init__(self, server: _MockServer) -> None:
-        self._server = server
-        self._running = False
-        self.context = ExitStack()
-
-    @property
-    def port(self) -> int:
-        return self._server.port
-
-    @property
-    def host(self) -> str:
-        return self._server.host
-
-    def set_responses(self, responses: Iterable["WSGIApplication"]) -> None:
-        assert not self._running, "responses cannot be set on running server"
-        self._server.mock.side_effect = responses
-
-    def start(self) -> None:
-        assert not self._running, "running server cannot be started"
-        self.context.enter_context(server_running(self._server))
-        self.context.enter_context(self._set_running())
-
-    @contextmanager
-    def _set_running(self) -> Iterator[None]:
-        self._running = True
-        try:
-            yield
-        finally:
-            self._running = False
-
-    def stop(self) -> None:
-        assert self._running, "idle server cannot be stopped"
-        self.context.close()
-
-    def get_requests(self) -> List[Dict[str, str]]:
-        """Get environ for each received request."""
-        assert not self._running, "cannot get mock from running server"
-        # Legacy: replace call[0][0] with call.args[0]
-        # when pip drops support for python3.7
-        return [call[0][0] for call in self._server.mock.call_args_list]
-
-
 @pytest.fixture
 def mock_server() -> Iterator[MockServer]:
     server = make_mock_server()

tests/functional/test_completion.py

@@ -5,8 +5,7 @@ from typing import TYPE_CHECKING, Tuple, Union
 
 import pytest
 
-from tests.conftest import ScriptFactory
-from tests.lib import PipTestEnvironment, TestData, TestPipResult
+from tests.lib import PipTestEnvironment, ScriptFactory, TestData, TestPipResult
 
 if TYPE_CHECKING:
     from typing import Protocol

tests/functional/test_download.py

@@ -14,15 +14,15 @@ import pytest
 
 from pip._internal.cli.status_codes import ERROR
 from pip._internal.utils.urls import path_to_url
-from tests.conftest import MockServer, ScriptFactory
 from tests.lib import (
     PipTestEnvironment,
+    ScriptFactory,
     TestData,
     TestPipResult,
     create_basic_sdist_for_package,
     create_really_basic_wheel,
 )
-from tests.lib.server import file_response
+from tests.lib.server import MockServer, file_response
 
 
 def fake_wheel(data: TestData, wheel_path: str) -> None:

tests/functional/test_help.py

@@ -5,8 +5,7 @@ import pytest
 from pip._internal.cli.status_codes import ERROR, SUCCESS
 from pip._internal.commands import commands_dict, create_command
 from pip._internal.exceptions import CommandError
-from tests.conftest import InMemoryPip
-from tests.lib import PipTestEnvironment
+from tests.lib import InMemoryPip, PipTestEnvironment
 
 
 def test_run_method_should_return_success_when_finds_command_name() -> None:

tests/functional/test_inspect.py

@@ -2,8 +2,7 @@ import json
 
 import pytest
 
-from tests.conftest import ScriptFactory
-from tests.lib import PipTestEnvironment, TestData
+from tests.lib import PipTestEnvironment, ScriptFactory, TestData
 
 
 @pytest.fixture(scope="session")

tests/functional/test_install.py

@@ -15,8 +15,8 @@ from pip._internal.cli.status_codes import ERROR, SUCCESS
 from pip._internal.models.index import PyPI, TestPyPI
 from pip._internal.utils.misc import rmtree
 from pip._internal.utils.urls import path_to_url
-from tests.conftest import CertFactory
 from tests.lib import (
+    CertFactory,
     PipTestEnvironment,
     ResolverVariant,
     TestData,

tests/functional/test_install_config.py

@@ -8,9 +8,9 @@ from typing import Callable, List
 
 import pytest
 
-from tests.conftest import CertFactory, MockServer, ScriptFactory
-from tests.lib import PipTestEnvironment, TestData
+from tests.lib import CertFactory, PipTestEnvironment, ScriptFactory, TestData
 from tests.lib.server import (
+    MockServer,
     authorization_response,
     file_response,
     make_mock_server,

tests/functional/test_list.py

@@ -5,9 +5,9 @@ from pathlib import Path
 import pytest
 
 from pip._internal.models.direct_url import DirectUrl, DirInfo
-from tests.conftest import ScriptFactory
 from tests.lib import (
     PipTestEnvironment,
+    ScriptFactory,
     TestData,
     _create_test_package,
     create_test_package_with_setup,

tests/lib/__init__.py

@@ -10,11 +10,12 @@ import textwrap
 from base64 import urlsafe_b64encode
 from contextlib import contextmanager
 from hashlib import sha256
-from io import BytesIO
+from io import BytesIO, StringIO
 from textwrap import dedent
 from typing import (
     TYPE_CHECKING,
     Any,
+    AnyStr,
     Callable,
     Dict,
     Iterable,
@@ -32,6 +33,7 @@ import pytest
 from pip._vendor.packaging.utils import canonicalize_name
 from scripttest import FoundDir, FoundFile, ProcResult, TestFileEnvironment
 
+from pip._internal.cli.main import main as pip_entry_point
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
 from pip._internal.locations import get_major_minor_version
@@ -43,12 +45,12 @@ from tests.lib.venv import VirtualEnvironment
 from tests.lib.wheel import make_wheel
 
 if TYPE_CHECKING:
-    # Literal was introduced in Python 3.8.
-    from typing import Literal
+    from typing import Literal, Protocol
 
     ResolverVariant = Literal["resolvelib", "legacy"]
-else:
-    ResolverVariant = str
+else:  # TODO: Remove this branch when dropping support for Python 3.7.
+    Protocol = object  # Protocol was introduced in Python 3.8.
+    ResolverVariant = str  # Literal was introduced in Python 3.8.
 
 DATA_DIR = pathlib.Path(__file__).parent.parent.joinpath("data").resolve()
 SRC_DIR = pathlib.Path(__file__).resolve().parent.parent.parent
@@ -1336,3 +1338,39 @@ def need_svn(fn: _Test) -> _Test:
 
 def need_mercurial(fn: _Test) -> _Test:
     return pytest.mark.mercurial(need_executable("Mercurial", ("hg", "version"))(fn))
+
+
+class InMemoryPipResult:
+    def __init__(self, returncode: int, stdout: str) -> None:
+        self.returncode = returncode
+        self.stdout = stdout
+
+
+class InMemoryPip:
+    def pip(self, *args: Union[str, pathlib.Path]) -> InMemoryPipResult:
+        orig_stdout = sys.stdout
+        stdout = StringIO()
+        sys.stdout = stdout
+        try:
+            returncode = pip_entry_point([os.fspath(a) for a in args])
+        except SystemExit as e:
+            if isinstance(e.code, int):
+                returncode = e.code
+            else:
+                returncode = int(bool(e.code))
+        finally:
+            sys.stdout = orig_stdout
+        return InMemoryPipResult(returncode, stdout.getvalue())
+
+
+class ScriptFactory(Protocol):
+    def __call__(
+        self,
+        tmpdir: pathlib.Path,
+        virtualenv: Optional[VirtualEnvironment] = None,
+        environ: Optional[Dict[AnyStr, AnyStr]] = None,
+    ) -> PipTestEnvironment:
+        ...
+
+
+CertFactory = Callable[[], str]

tests/lib/compat.py

@@ -2,32 +2,13 @@
 
 import contextlib
 import signal
-from typing import Iterable, Iterator
-
-
-@contextlib.contextmanager
-def nullcontext() -> Iterator[None]:
-    """
-    Context manager that does no additional processing.
-
-    Used as a stand-in for a normal context manager, when a particular block of
-    code is only sometimes used with a normal context manager:
-
-        cm = optional_cm if condition else nullcontext()
-        with cm:
-            # Perform operation, using optional_cm if condition is True
-
-    TODO: Replace with contextlib.nullcontext after dropping Python 3.6
-    support.
-    """
-    yield
-
+from typing import Callable, ContextManager, Iterable, Iterator
 
 # Applies on Windows.
 if not hasattr(signal, "pthread_sigmask"):
     # We're not relying on this behavior anywhere currently, it's just best
     # practice.
-    blocked_signals = nullcontext
+    blocked_signals: Callable[[], ContextManager[None]] = contextlib.nullcontext
 else:
 
     @contextlib.contextmanager

tests/lib/server.py

@@ -2,9 +2,9 @@ import pathlib
 import ssl
 import threading
 from base64 import b64encode
-from contextlib import contextmanager
+from contextlib import ExitStack, contextmanager
 from textwrap import dedent
-from typing import TYPE_CHECKING, Any, Callable, Dict, Iterable, Iterator
+from typing import TYPE_CHECKING, Any, Callable, Dict, Iterable, Iterator, List
 from unittest.mock import Mock
 
 from werkzeug.serving import BaseWSGIServer, WSGIRequestHandler
@@ -18,7 +18,7 @@ if TYPE_CHECKING:
 Body = Iterable[bytes]
 
 
-class MockServer(BaseWSGIServer):
+class _MockServer(BaseWSGIServer):
     mock: Mock = Mock()
 
 
@@ -64,7 +64,7 @@ def _mock_wsgi_adapter(
     return adapter
 
 
-def make_mock_server(**kwargs: Any) -> MockServer:
+def make_mock_server(**kwargs: Any) -> _MockServer:
     """Creates a mock HTTP(S) server listening on a random port on localhost.
 
     The `mock` property of the returned server provides and records all WSGI
@@ -189,3 +189,46 @@ def authorization_response(path: pathlib.Path) -> "WSGIApplication":
         return [path.read_bytes()]
 
     return responder
+
+
+class MockServer:
+    def __init__(self, server: _MockServer) -> None:
+        self._server = server
+        self._running = False
+        self.context = ExitStack()
+
+    @property
+    def port(self) -> int:
+        return self._server.port
+
+    @property
+    def host(self) -> str:
+        return self._server.host
+
+    def set_responses(self, responses: Iterable["WSGIApplication"]) -> None:
+        assert not self._running, "responses cannot be set on running server"
+        self._server.mock.side_effect = responses
+
+    def start(self) -> None:
+        assert not self._running, "running server cannot be started"
+        self.context.enter_context(server_running(self._server))
+        self.context.enter_context(self._set_running())
+
+    @contextmanager
+    def _set_running(self) -> Iterator[None]:
+        self._running = True
+        try:
+            yield
+        finally:
+            self._running = False
+
+    def stop(self) -> None:
+        assert self._running, "idle server cannot be stopped"
+        self.context.close()
+
+    def get_requests(self) -> List[Dict[str, str]]:
+        """Get environ for each received request."""
+        assert not self._running, "cannot get mock from running server"
+        # Legacy: replace call[0][0] with call.args[0]
+        # when pip drops support for python3.7
+        return [call[0][0] for call in self._server.mock.call_args_list]