diff --git a/tests/conftest.py b/tests/conftest.py
index fd7ebde..3026db7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,6 @@
 # stdlib
 import datetime
+from typing import Iterator
 
 # 3rd party
 import pytest
@@ -12,11 +13,11 @@
 
 
 @pytest.fixture()
-def tar_regression(datadir, original_datadir, request) -> AdvancedFileRegressionFixture:
+def tar_regression(datadir, original_datadir, request) -> AdvancedFileRegressionFixture:  # noqa: MAN001
 	return TarFileRegressionFixture(datadir, original_datadir, request)
 
 
 @pytest.fixture()
-def fixed_datetime():
+def fixed_datetime() -> Iterator:
 	with with_fixed_datetime(datetime.datetime.fromtimestamp(1602552000.0)):
 		yield
diff --git a/tests/test_build.py b/tests/test_build.py
index cd2e2b1..041f535 100644
--- a/tests/test_build.py
+++ b/tests/test_build.py
@@ -1,6 +1,6 @@
 # stdlib
 import tempfile
-from typing import Any, Dict
+from typing import Any, Dict, List
 
 # 3rd party
 import pytest
@@ -124,7 +124,7 @@ def test_build_success(
 	advanced_data_regression.check(data)
 
 
-def check_built_wheel(filename: PathPlus, tar_regression: TarFileRegressionFixture):
+def check_built_wheel(filename: PathPlus, tar_regression: TarFileRegressionFixture) -> List[str]:
 	assert filename.is_file()
 
 	with TarFile.open(filename) as zip_file:
diff --git a/tests/test_build_conda.py b/tests/test_build_conda.py
index 5818f96..234fbb1 100644
--- a/tests/test_build_conda.py
+++ b/tests/test_build_conda.py
@@ -16,7 +16,7 @@
 from whey_conda import CondaBuilder
 
 
-def test_info_dir(tmp_pathplus):
+def test_info_dir(tmp_pathplus: PathPlus) -> None:
 
 	(tmp_pathplus / "pyproject.toml").write_text(DESCRIPTION)
 
@@ -44,7 +44,7 @@ def test_info_dir(tmp_pathplus):
 				("domdfcoding", "mathematical"),
 				]
 		)
-def test_build(username, repository, tmp_pathplus, monkeypatch):
+def test_build(username: str, repository: str, tmp_pathplus: PathPlus, monkeypatch):
 	# Monkeypatch dulwich so it doesn't try to use the global config.
 	monkeypatch.setattr(StackedConfig, "default_backends", lambda *args: [])
 	email = b"repo-helper[bot] <74742576+repo-helper[bot]@users.noreply.github.com>"
diff --git a/tests/utils.py b/tests/utils.py
index dab8ad3..98a4dbb 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -47,11 +47,11 @@ def open(
 
 class TarFileRegressionFixture(AdvancedFileRegressionFixture):
 
-	def check_archive(self, tar_file: TarFile, filename: str, **kwargs):
+	def check_archive(self, tar_file: TarFile, filename: str, **kwargs) -> None:
 		self.check(tar_file.read_text(filename), **kwargs)
 
 
-def get_stdouterr(capsys, tmpdir: pathlib.Path) -> Dict[str, str]:
+def get_stdouterr(capsys, tmpdir: pathlib.Path) -> Dict[str, str]:  # noqa: MAN001
 
 	outerr = capsys.readouterr()
 
diff --git a/whey_conda/__init__.py b/whey_conda/__init__.py
index 2eb6718..cfa5ec1 100644
--- a/whey_conda/__init__.py
+++ b/whey_conda/__init__.py
@@ -141,11 +141,11 @@ def info_dir(self) -> PathPlus:
 		info_dir.maybe_make()
 		return info_dir
 
-	def _echo_if_v(self, *args, **kwargs):
+	def _echo_if_v(self, *args, **kwargs) -> None:
 		if self.verbose:
 			self._echo(*args, **kwargs)
 
-	def write_conda_index(self, build_number: int = 1):
+	def write_conda_index(self, build_number: int = 1) -> None:
 		"""
 		Write the conda ``index.json`` file.
 
@@ -178,7 +178,7 @@ def write_conda_index(self, build_number: int = 1):
 		index_json_file.dump_json(index, indent=2)
 		self.report_written(index_json_file)
 
-	def write_conda_about(self):
+	def write_conda_about(self) -> None:
 		"""
 		Write the conda ``about.json`` file.
 
@@ -304,7 +304,7 @@ def create_conda_archive(self, wheel_contents_dir: PathLike, build_number: int =
 
 		return os.path.basename(conda_filename)
 
-	def write_license(self, dest_dir: PathPlus, dest_filename: str = "LICENSE"):
+	def write_license(self, dest_dir: PathPlus, dest_filename: str = "LICENSE") -> None:
 		"""
 		Write the ``LICENSE`` file.
 
@@ -384,7 +384,7 @@ def build_conda(self) -> str:
 	build = build_conda
 
 
-def pip_install_wheel(wheel_file: PathLike, target_dir: PathLike, verbose: bool = False):
+def pip_install_wheel(wheel_file: PathLike, target_dir: PathLike, verbose: bool = False) -> None:
 	command = [
 			"pip",
 			"install",