mypy: test helpers: conftest.py mixins.py osinfo.py

3 files changed, 33 insertions, 28 deletions

diff --git a/tests/conftest.py b/tests/conftest.py
index d45cae1d..d87c1289 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -11,7 +11,9 @@ import os
 import sys
 import sysconfig
 import warnings
+
 from pathlib import Path
+from typing import Generator, Optional
 
 import pytest
 
@@ -30,7 +32,7 @@ pytest_plugins = "tests.balance_xdist_plugin"
 
 
 @pytest.fixture(autouse=True)
-def set_warnings():
+def set_warnings() -> None:
     """Configure warnings to show while running tests."""
     warnings.simplefilter("default")
     warnings.simplefilter("once", DeprecationWarning)
@@ -61,7 +63,7 @@ def set_warnings():
 
 
 @pytest.fixture(autouse=True)
-def reset_sys_path():
+def reset_sys_path() -> Generator[None, None, None]:
     """Clean up sys.path changes around every test."""
     sys_path = list(sys.path)
     yield
@@ -69,7 +71,7 @@ def reset_sys_path():
 
 
 @pytest.fixture(autouse=True)
-def reset_environment():
+def reset_environment() -> Generator[None, None, None]:
     """Make sure a test setting an envvar doesn't leak into another test."""
     old_environ = os.environ.copy()
     yield
@@ -78,14 +80,14 @@ def reset_environment():
 
 
 @pytest.fixture(autouse=True)
-def reset_filesdotpy_globals():
+def reset_filesdotpy_globals() -> Generator[None, None, None]:
     """coverage/files.py has some unfortunate globals. Reset them every test."""
     set_relative_directory()
     yield
 
 WORKER = os.environ.get("PYTEST_XDIST_WORKER", "none")
 
-def pytest_sessionstart():
+def pytest_sessionstart() -> None:
     """Run once at the start of the test session."""
     # Only in the main process...
     if WORKER == "none":
@@ -96,7 +98,7 @@ def pytest_sessionstart():
         # subcover.pth is deleted by pytest_sessionfinish below.
 
 
-def pytest_sessionfinish():
+def pytest_sessionfinish() -> None:
     """Hook the end of a test session, to clean up."""
     # This is called by each of the workers and by the main process.
     if WORKER == "none":
@@ -106,7 +108,7 @@ def pytest_sessionfinish():
                 pth_file.unlink()
 
 
-def possible_pth_dirs():
+def possible_pth_dirs() -> Generator[Path, None, None]:
     """Produce a sequence of directories for trying to write .pth files."""
     # First look through sys.path, and if we find a .pth file, then it's a good
     # place to put ours.
@@ -120,7 +122,7 @@ def possible_pth_dirs():
     yield Path(sysconfig.get_path("purelib"))       # pragma: cant happen
 
 
-def find_writable_pth_directory():
+def find_writable_pth_directory() -> Optional[Path]:
     """Find a place to write a .pth file."""
     for pth_dir in possible_pth_dirs():             # pragma: part covered
         try_it = pth_dir / f"touch_{WORKER}.it"
diff --git a/tests/mixins.py b/tests/mixins.py
index f8cc5085..97fd2a91 100644
--- a/tests/mixins.py
+++ b/tests/mixins.py
@@ -12,8 +12,7 @@ import os
 import os.path
 import sys
 
-from typing import Iterator, Tuple
-from typing import Iterable, Optional
+from typing import Any, Callable, Iterable, Iterator, Optional, Tuple
 
 import pytest
 
@@ -25,7 +24,11 @@ class PytestBase:
     """A base class to connect to pytest in a test class hierarchy."""
 
     @pytest.fixture(autouse=True)
-    def connect_to_pytest(self, request, monkeypatch) -> None:
+    def connect_to_pytest(
+        self,
+        request: pytest.FixtureRequest,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
         """Captures pytest facilities for use by other test helpers."""
         # pylint: disable=attribute-defined-outside-init
         self._pytest_request = request
@@ -36,15 +39,15 @@ class PytestBase:
         """Per-test initialization. Override this as you wish."""
         pass
 
-    def addCleanup(self, fn, *args) -> None:
+    def addCleanup(self, fn: Callable[..., None], *args: Any) -> None:
         """Like unittest's addCleanup: code to call when the test is done."""
         self._pytest_request.addfinalizer(lambda: fn(*args))
 
-    def set_environ(self, name, value) -> None:
+    def set_environ(self, name: str, value: str) -> None:
         """Set an environment variable `name` to be `value`."""
         self._monkeypatch.setenv(name, value)
 
-    def del_environ(self, name) -> None:
+    def del_environ(self, name: str) -> None:
         """Delete an environment variable, unless we set it."""
         self._monkeypatch.delenv(name, raising=False)
 
@@ -133,12 +136,12 @@ class StdStreamCapturingMixin:
 
     def stdouterr(self) -> Tuple[str, str]:
         """Returns (out, err), two strings for stdout and stderr."""
-        return self.capsys.readouterr()
+        return self.capsys.readouterr()             # type: ignore[no-any-return]
 
     def stdout(self) -> str:
         """Returns a string, the captured stdout."""
-        return self.capsys.readouterr().out
+        return self.capsys.readouterr().out         # type: ignore[no-any-return]
 
     def stderr(self) -> str:
         """Returns a string, the captured stderr."""
-        return self.capsys.readouterr().err
+        return self.capsys.readouterr().err         # type: ignore[no-any-return]
diff --git a/tests/osinfo.py b/tests/osinfo.py
index ec34c709..57d11273 100644
--- a/tests/osinfo.py
+++ b/tests/osinfo.py
@@ -3,12 +3,12 @@
 
 """OS information for testing."""
 
-from coverage import env
+import sys
 
 
-if env.WINDOWS:
+if sys.platform == "win32":
     # Windows implementation
-    def process_ram():
+    def process_ram() -> int:
         """How much RAM is this process using? (Windows)"""
         import ctypes
         # From: http://lists.ubuntu.com/archives/bazaar-commits/2009-February/011990.html
@@ -38,35 +38,35 @@ if env.WINDOWS:
             return 0                # pragma: cant happen
         return mem_struct.PrivateUsage
 
-elif env.LINUX:
+elif sys.platform.startswith("linux"):
     # Linux implementation
     import os
 
     _scale = {'kb': 1024, 'mb': 1024*1024}
 
-    def _VmB(key):
+    def _VmB(key: str) -> int:
         """Read the /proc/PID/status file to find memory use."""
         try:
             # Get pseudo file /proc/<pid>/status
-            with open('/proc/%d/status' % os.getpid()) as t:
+            with open(f"/proc/{os.getpid()}/status") as t:
                 v = t.read()
         except OSError:             # pragma: cant happen
             return 0    # non-Linux?
         # Get VmKey line e.g. 'VmRSS:  9999  kB\n ...'
         i = v.index(key)
-        v = v[i:].split(None, 3)
-        if len(v) < 3:              # pragma: part covered
+        vp = v[i:].split(None, 3)
+        if len(vp) < 3:             # pragma: part covered
             return 0                # pragma: cant happen
         # Convert Vm value to bytes.
-        return int(float(v[1]) * _scale[v[2].lower()])
+        return int(float(vp[1]) * _scale[vp[2].lower()])
 
-    def process_ram():
+    def process_ram() -> int:
         """How much RAM is this process using? (Linux implementation)"""
         return _VmB('VmRSS')
 
 else:
     # Generic implementation.
-    def process_ram():
+    def process_ram() -> int:
         """How much RAM is this process using? (stdlib implementation)"""
         import resource
         return resource.getrusage(resource.RUSAGE_SELF).ru_maxrss