Fully type certbot-compatibility-test (#9133)

* Finish typing the module

* Use cast

* Precise type

9 files changed, 168 insertions, 115 deletions

diff --git a/certbot-compatibility-test/certbot_compatibility_test/configurators/apache/common.py b/certbot-compatibility-test/certbot_compatibility_test/configurators/apache/common.py
index e8cbdcb06..fda51f3a0 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/configurators/apache/common.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/configurators/apache/common.py
@@ -1,21 +1,26 @@
 """Provides a common base for Apache proxies"""
+import argparse
 import os
 import shutil
 import subprocess
+from typing import Set
+from typing import Tuple
 from unittest import mock
 
-from certbot import errors as le_errors, configuration
-from certbot import util as certbot_util
 from certbot_apache._internal import entrypoint
 from certbot_compatibility_test import errors
 from certbot_compatibility_test import util
 from certbot_compatibility_test.configurators import common as configurators_common
 
+from certbot import configuration
+from certbot import errors as le_errors
+from certbot import util as certbot_util
+
 
 class Proxy(configurators_common.Proxy):
     """A common base for Apache test configurators"""
 
-    def __init__(self, args):
+    def __init__(self, args: argparse.Namespace) -> None:
         """Initializes the plugin with the given command line args"""
         super().__init__(args)
         self.le_config.apache_le_vhost_ext = "-le-ssl.conf"
@@ -27,7 +32,7 @@ class Proxy(configurators_common.Proxy):
         mock_display.side_effect = le_errors.PluginError(
             "Unable to determine vhost")
 
-    def load_config(self):
+    def load_config(self) -> str:
         """Loads the next configuration for the plugin to test"""
         config = super().load_config()
         self._all_names, self._test_names = _get_names(config)
@@ -47,7 +52,7 @@ class Proxy(configurators_common.Proxy):
 
         return config
 
-    def _prepare_configurator(self):
+    def _prepare_configurator(self) -> None:
         """Prepares the Apache plugin for testing"""
         for k in entrypoint.ENTRYPOINT.OS_DEFAULTS.__dict__.keys():
             setattr(self.le_config, "apache_" + k,
@@ -58,13 +63,13 @@ class Proxy(configurators_common.Proxy):
             name="apache")
         self._configurator.prepare()
 
-    def cleanup_from_tests(self):
+    def cleanup_from_tests(self) -> None:
         """Performs any necessary cleanup from running plugin tests"""
         super().cleanup_from_tests()
         mock.patch.stopall()
 
 
-def _get_server_root(config):
+def _get_server_root(config: str) -> str:
     """Returns the server root directory in config"""
     subdirs = [
         name for name in os.listdir(config)
@@ -76,7 +81,7 @@ def _get_server_root(config):
     return os.path.join(config, subdirs[0].rstrip())
 
 
-def _get_names(config):
+def _get_names(config: str) -> Tuple[Set[str], Set[str]]:
     """Returns all and testable domain names in config"""
     all_names = set()
     non_ip_names = set()
diff --git a/certbot-compatibility-test/certbot_compatibility_test/configurators/common.py b/certbot-compatibility-test/certbot_compatibility_test/configurators/common.py
index 10626f9b7..432f48f32 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/configurators/common.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/configurators/common.py
@@ -1,15 +1,28 @@
 """Provides a common base for configurator proxies"""
 from abc import abstractmethod
+import argparse
 import logging
 import os
 import shutil
 import tempfile
+from typing import Iterable
+from typing import List
+from typing import Optional
+from typing import overload
+from typing import Set
+from typing import Tuple
+from typing import Type
+from typing import Union
 
-from certbot._internal import constants
-from certbot_compatibility_test import interfaces
 from certbot_compatibility_test import errors
+from certbot_compatibility_test import interfaces
 from certbot_compatibility_test import util
 
+from acme import challenges
+from acme.challenges import Challenge
+from certbot._internal import constants
+from certbot.achallenges import AnnotatedChallenge
+
 logger = logging.getLogger(__name__)
 
 
@@ -17,10 +30,10 @@ class Proxy(interfaces.ConfiguratorProxy):
     """A common base for compatibility test configurators"""
 
     @classmethod
-    def add_parser_arguments(cls, parser):
+    def add_parser_arguments(cls, parser: argparse.ArgumentParser) -> None:
         """Adds command line arguments needed by the plugin"""
 
-    def __init__(self, args):
+    def __init__(self, args: argparse.Namespace) -> None:
         """Initializes the plugin with the given command line args"""
         super().__init__(args)
         self._temp_dir = tempfile.mkdtemp()
@@ -37,25 +50,34 @@ class Proxy(interfaces.ConfiguratorProxy):
         self.http_port = 80
         self.https_port = 443
         self._configurator: interfaces.Configurator
-        self._all_names = None
-        self._test_names = None
+        self._all_names: Optional[Set[str]] = None
+        self._test_names: Optional[Set[str]] = None
 
-    def has_more_configs(self):
+    def has_more_configs(self) -> bool:
         """Returns true if there are more configs to test"""
         return bool(self._configs)
 
     @abstractmethod
-    def cleanup_from_tests(self):
+    def cleanup_from_tests(self) -> None:
         """Performs any necessary cleanup from running plugin tests"""
 
-    def load_config(self):
+    def load_config(self) -> str:
         """Returns the next config directory to be tested"""
         shutil.rmtree(self.le_config.work_dir, ignore_errors=True)
         backup = os.path.join(self.le_config.work_dir, constants.BACKUP_DIR)
         os.makedirs(backup)
         return self._configs.pop()
 
-    def copy_certs_and_keys(self, cert_path, key_path, chain_path=None):
+    @overload
+    def copy_certs_and_keys(self, cert_path: str, key_path: str,
+                            chain_path: str) -> Tuple[str, str, str]: ...
+
+    @overload
+    def copy_certs_and_keys(self, cert_path: str, key_path: str,
+                            chain_path: Optional[str]) -> Tuple[str, str, Optional[str]]: ...
+
+    def copy_certs_and_keys(self, cert_path: str, key_path: str,
+                            chain_path: Optional[str] = None) -> Tuple[str, str, Optional[str]]:
         """Copies certs and keys into the temporary directory"""
         cert_and_key_dir = os.path.join(self._temp_dir, "certs_and_keys")
         if not os.path.isdir(cert_and_key_dir):
@@ -72,68 +94,67 @@ class Proxy(interfaces.ConfiguratorProxy):
 
         return cert, key, chain
 
-    def get_all_names_answer(self):
+    def get_all_names_answer(self) -> Set[str]:
         """Returns the set of domain names that the plugin should find"""
         if self._all_names:
             return self._all_names
         raise errors.Error("No configuration file loaded")
 
-    def get_testable_domain_names(self):
+    def get_testable_domain_names(self) -> Set[str]:
         """Returns the set of domain names that can be tested against"""
         if self._test_names:
             return self._test_names
         return {"example.com"}
 
-    def deploy_cert(self, domain, cert_path, key_path, chain_path=None,
-                    fullchain_path=None):
+    def deploy_cert(self, domain: str, cert_path: str, key_path: str, chain_path: str,
+                    fullchain_path: str) -> None:
         """Installs cert"""
-        cert_path, key_path, chain_path = self.copy_certs_and_keys(
-            cert_path, key_path, chain_path)
+        cert_path, key_path, chain_path = self.copy_certs_and_keys(cert_path, key_path, chain_path)
         if not self._configurator:
             raise ValueError("Configurator plugin is not set.")
         self._configurator.deploy_cert(
             domain, cert_path, key_path, chain_path, fullchain_path)
 
-
-    def cleanup(self, achalls):
+    def cleanup(self, achalls: List[AnnotatedChallenge]) -> None:
         self._configurator.cleanup(achalls)
 
-    def config_test(self):
+    def config_test(self) -> None:
         self._configurator.config_test()
 
-    def enhance(self, domain, enhancement, options = None):
+    def enhance(self, domain: str, enhancement: str,
+                options: Optional[Union[List[str], str]] = None) -> None:
         self._configurator.enhance(domain, enhancement, options)
 
-    def get_all_names(self):
+    def get_all_names(self) -> Iterable[str]:
         return self._configurator.get_all_names()
 
-    def get_chall_pref(self, domain):
+    def get_chall_pref(self, domain: str) -> Iterable[Type[Challenge]]:
         return self._configurator.get_chall_pref(domain)
 
     @classmethod
-    def inject_parser_options(cls, parser, name):
+    def inject_parser_options(cls, parser: argparse.ArgumentParser, name: str) -> None:
         pass
 
-    def more_info(self):
+    def more_info(self) -> str:
         return self._configurator.more_info()
 
-    def perform(self, achalls):
+    def perform(self, achalls: List[AnnotatedChallenge]) -> List[challenges.ChallengeResponse]:
         return self._configurator.perform(achalls)
 
-    def prepare(self):
+    def prepare(self) -> None:
         self._configurator.prepare()
 
-    def recovery_routine(self):
+    def recovery_routine(self) -> None:
         self._configurator.recovery_routine()
 
-    def restart(self):
+    def restart(self) -> None:
         self._configurator.restart()
 
-    def rollback_checkpoints(self, rollback = 1):
+    def rollback_checkpoints(self, rollback: int = 1) -> None:
         self._configurator.rollback_checkpoints(rollback)
 
-    def save(self, title = None, temporary = False):
+    def save(self, title: Optional[str] = None, temporary: bool = False) -> None:
         self._configurator.save(title, temporary)
 
-    def supported_enhancements(self):
+    def supported_enhancements(self) -> List[str]:
         return self._configurator.supported_enhancements()
diff --git a/certbot-compatibility-test/certbot_compatibility_test/configurators/nginx/common.py b/certbot-compatibility-test/certbot_compatibility_test/configurators/nginx/common.py
index b9df1a6b2..f08d6b1b8 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/configurators/nginx/common.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/configurators/nginx/common.py
@@ -4,8 +4,8 @@ import shutil
 import subprocess
 from typing import cast
 from typing import Set
+from typing import Tuple
 
-from certbot import configuration
 from certbot_compatibility_test import errors
 from certbot_compatibility_test import interfaces
 from certbot_compatibility_test import util
@@ -13,11 +13,13 @@ from certbot_compatibility_test.configurators import common as configurators_com
 from certbot_nginx._internal import configurator
 from certbot_nginx._internal import constants
 
+from certbot import configuration
+
 
 class Proxy(configurators_common.Proxy):
     """A common base for Nginx test configurators"""
 
-    def load_config(self):
+    def load_config(self) -> str:
         """Loads the next configuration for the plugin to test"""
         config = super().load_config()
         self._all_names, self._test_names = _get_names(config)
@@ -40,7 +42,7 @@ class Proxy(configurators_common.Proxy):
 
         return config
 
-    def _prepare_configurator(self):
+    def _prepare_configurator(self) -> None:
         """Prepares the Nginx plugin for testing"""
         for k in constants.CLI_DEFAULTS:
             setattr(self.le_config, "nginx_" + k, constants.os_constant(k))
@@ -50,11 +52,11 @@ class Proxy(configurators_common.Proxy):
             config=conf, name="nginx"))
         self._configurator.prepare()
 
-    def cleanup_from_tests(self):
+    def cleanup_from_tests(self) -> None:
         """Performs any necessary cleanup from running plugin tests"""
 
 
-def _get_server_root(config):
+def _get_server_root(config: str) -> str:
     """Returns the server root directory in config"""
     subdirs = [
         name for name in os.listdir(config)
@@ -66,7 +68,7 @@ def _get_server_root(config):
     return os.path.join(config, subdirs[0].rstrip())
 
 
-def _get_names(config):
+def _get_names(config: str) -> Tuple[Set[str], Set[str]]:
     """Returns all and testable domain names in config"""
     all_names: Set[str] = set()
     for root, _dirs, files in os.walk(config):
@@ -77,7 +79,7 @@ def _get_names(config):
     return all_names, non_ip_names
 
 
-def _get_server_names(root, filename):
+def _get_server_names(root: str, filename: str) -> Set[str]:
     """Returns all names in a config file path"""
     all_names = set()
     with open(os.path.join(root, filename)) as f:
diff --git a/certbot-compatibility-test/certbot_compatibility_test/interfaces.py b/certbot-compatibility-test/certbot_compatibility_test/interfaces.py
index 62c4fd690..1f696ac93 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/interfaces.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/interfaces.py
@@ -1,8 +1,12 @@
 """Certbot compatibility test interfaces"""
 from abc import ABCMeta
 from abc import abstractmethod
+import argparse
+from typing import cast
+from typing import Set
 
 from certbot import interfaces
+from certbot.configuration import NamespaceConfig
 
 
 class PluginProxy(interfaces.Plugin, metaclass=ABCMeta):
@@ -16,16 +20,16 @@ class PluginProxy(interfaces.Plugin, metaclass=ABCMeta):
 
     @classmethod
     @abstractmethod
-    def add_parser_arguments(cls, parser):
+    def add_parser_arguments(cls, parser: argparse.ArgumentParser) -> None:
         """Adds command line arguments needed by the parser"""
 
     @abstractmethod
-    def __init__(self, args):
+    def __init__(self, args: argparse.Namespace) -> None:
         """Initializes the plugin with the given command line args"""
-        super().__init__(args, 'proxy')
+        super().__init__(cast(NamespaceConfig, args), 'proxy')
 
     @abstractmethod
-    def cleanup_from_tests(self):
+    def cleanup_from_tests(self) -> None:
         """Performs any necessary cleanup from running plugin tests.
 
         This is guaranteed to be called before the program exits.
@@ -33,15 +37,15 @@ class PluginProxy(interfaces.Plugin, metaclass=ABCMeta):
         """
 
     @abstractmethod
-    def has_more_configs(self):
+    def has_more_configs(self) -> bool:
         """Returns True if there are more configs to test"""
 
     @abstractmethod
-    def load_config(self):
+    def load_config(self) -> str:
         """Loads the next config and returns its name"""
 
     @abstractmethod
-    def get_testable_domain_names(self):
+    def get_testable_domain_names(self) -> Set[str]:
         """Returns the domain names that can be used in testing"""
 
 
@@ -53,7 +57,7 @@ class InstallerProxy(PluginProxy, interfaces.Installer, metaclass=ABCMeta):
     """Wraps a Certbot installer"""
 
     @abstractmethod
-    def get_all_names_answer(self):
+    def get_all_names_answer(self) -> Set[str]:
         """Returns all names that should be found by the installer"""
 
 
diff --git a/certbot-compatibility-test/certbot_compatibility_test/test_driver.py b/certbot-compatibility-test/certbot_compatibility_test/test_driver.py
index 62098488f..1b27a2195 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/test_driver.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/test_driver.py
@@ -5,13 +5,26 @@ import filecmp
 import logging
 import os
 import shutil
+import socket
 import sys
 import tempfile
 import time
+from typing import Any
+from typing import Dict
+from typing import Generator
+from typing import Iterable
 from typing import List
+from typing import Optional
 from typing import Tuple
+from typing import Type
 
-import OpenSSL
+from certbot_compatibility_test import errors
+from certbot_compatibility_test import util
+from certbot_compatibility_test import validator
+from certbot_compatibility_test.configurators import common
+from certbot_compatibility_test.configurators.apache import common as a_common
+from certbot_compatibility_test.configurators.nginx import common as n_common
+from OpenSSL import crypto
 from urllib3.util import connection
 
 from acme import challenges
@@ -19,14 +32,9 @@ from acme import crypto_util
 from acme import messages
 from certbot import achallenges
 from certbot import errors as le_errors
-from certbot.display import util as display_util
 from certbot._internal.display import obj as display_obj
+from certbot.display import util as display_util
 from certbot.tests import acme_util
-from certbot_compatibility_test import errors
-from certbot_compatibility_test import util
-from certbot_compatibility_test import validator
-from certbot_compatibility_test.configurators.apache import common as a_common
-from certbot_compatibility_test.configurators.nginx import common as n_common
 
 DESCRIPTION = """
 Tests Certbot plugins against different server configurations. It is
@@ -35,13 +43,13 @@ tests that the plugin supports are performed.
 
 """
 
-PLUGINS = {"apache": a_common.Proxy, "nginx": n_common.Proxy}
+PLUGINS: Dict[str, Type[common.Proxy]] = {"apache": a_common.Proxy, "nginx": n_common.Proxy}
 
 
 logger = logging.getLogger(__name__)
 
 
-def test_authenticator(plugin, config, temp_dir):
+def test_authenticator(plugin: common.Proxy, config: str, temp_dir: str) -> bool:
     """Tests authenticator, returning True if the tests are successful"""
     backup = _create_backup(config, temp_dir)
 
@@ -96,7 +104,7 @@ def test_authenticator(plugin, config, temp_dir):
     return success
 
 
-def _create_achalls(plugin):
+def _create_achalls(plugin: common.Proxy) -> List[achallenges.AnnotatedChallenge]:
     """Returns a list of annotated challenges to test on plugin"""
     achalls = []
     names = plugin.get_testable_domain_names()
@@ -117,7 +125,8 @@ def _create_achalls(plugin):
     return achalls
 
 
-def test_installer(args, plugin, config, temp_dir):
+def test_installer(args: argparse.Namespace, plugin: common.Proxy, config: str,
+                   temp_dir: str) -> bool:
     """Tests plugin as an installer"""
     backup = _create_backup(config, temp_dir)
 
@@ -137,13 +146,12 @@ def test_installer(args, plugin, config, temp_dir):
     return names_match and success and good_rollback
 
 
-def test_deploy_cert(plugin, temp_dir, domains):
+def test_deploy_cert(plugin: common.Proxy, temp_dir: str, domains: List[str]) -> bool:
     """Tests deploy_cert returning True if the tests are successful"""
     cert = crypto_util.gen_ss_cert(util.KEY, domains)
     cert_path = os.path.join(temp_dir, "cert.pem")
     with open(cert_path, "wb") as f:
-        f.write(OpenSSL.crypto.dump_certificate(
-            OpenSSL.crypto.FILETYPE_PEM, cert))
+        f.write(crypto.dump_certificate(crypto.FILETYPE_PEM, cert))
 
     for domain in domains:
         try:
@@ -171,7 +179,7 @@ def test_deploy_cert(plugin, temp_dir, domains):
     return success
 
 
-def test_enhancements(plugin, domains):
+def test_enhancements(plugin: common.Proxy, domains: Iterable[str]) -> bool:
     """Tests supported enhancements returning True if successful"""
     supported = plugin.supported_enhancements()
 
@@ -216,7 +224,7 @@ def test_enhancements(plugin, domains):
     return success
 
 
-def _save_and_restart(plugin, title=None):
+def _save_and_restart(plugin: common.Proxy, title: Optional[str] = None) -> bool:
     """Saves and restart the plugin, returning True if no errors occurred"""
     try:
         plugin.save(title)
@@ -227,7 +235,7 @@ def _save_and_restart(plugin, title=None):
         return False
 
 
-def test_rollback(plugin, config, backup):
+def test_rollback(plugin: common.Proxy, config: str, backup: str) -> bool:
     """Tests the rollback checkpoints function"""
     try:
         plugin.rollback_checkpoints(1337)
@@ -242,7 +250,7 @@ def test_rollback(plugin, config, backup):
     return True
 
 
-def _create_backup(config, temp_dir):
+def _create_backup(config: str, temp_dir: str) -> str:
     """Creates a backup of config in temp_dir"""
     backup = os.path.join(temp_dir, "backup")
     shutil.rmtree(backup, ignore_errors=True)
@@ -251,7 +259,7 @@ def _create_backup(config, temp_dir):
     return backup
 
 
-def _dirs_are_unequal(dir1, dir2):
+def _dirs_are_unequal(dir1: str, dir2: str) -> bool:
     """Returns True if dir1 and dir2 are unequal"""
     dircmps = [filecmp.dircmp(dir1, dir2)]
     while dircmps:
@@ -283,7 +291,7 @@ def _dirs_are_unequal(dir1, dir2):
     return False
 
 
-def get_args():
+def get_args() -> argparse.Namespace:
     """Returns parsed command line arguments."""
     parser = argparse.ArgumentParser(
         description=DESCRIPTION,
@@ -320,7 +328,7 @@ def get_args():
     return args
 
 
-def setup_logging(args):
+def setup_logging(args: argparse.Namespace) -> None:
     """Prepares logging for the program"""
     handler = logging.StreamHandler()
 
@@ -329,13 +337,13 @@ def setup_logging(args):
     root_logger.addHandler(handler)
 
 
-def setup_display():
+def setup_display() -> None:
     """"Prepares a display utility instance for the Certbot plugins """
     displayer = display_util.NoninteractiveDisplay(sys.stdout)
     display_obj.set_display(displayer)
 
 
-def main():
+def main() -> None:
     """Main test script execution."""
     args = get_args()
     setup_logging(args)
@@ -379,11 +387,12 @@ def main():
 
 
 @contextlib.contextmanager
-def _fake_dns_resolution(resolved_ip):
+def _fake_dns_resolution(resolved_ip: str) -> Generator[None, None, None]:
     """Monkey patch urllib3 to make any hostname be resolved to the provided IP"""
     _original_create_connection = connection.create_connection
 
-    def _patched_create_connection(address, *args, **kwargs):
+    def _patched_create_connection(address: Tuple[str, str],
+                                   *args: Any, **kwargs: Any) -> socket.socket:
         _, port = address
         return _original_create_connection((resolved_ip, port), *args, **kwargs)
 
diff --git a/certbot-compatibility-test/certbot_compatibility_test/util.py b/certbot-compatibility-test/certbot_compatibility_test/util.py
index 3465b7143..2a69d3835 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/util.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/util.py
@@ -6,11 +6,11 @@ import re
 import shutil
 import tarfile
 
+from certbot_compatibility_test import errors
 import josepy as jose
 
 from certbot._internal import constants
 from certbot.tests import util as test_util
-from certbot_compatibility_test import errors
 
 _KEY_BASE = "rsa2048_key.pem"
 KEY_PATH = test_util.vector_path(_KEY_BASE)
@@ -19,7 +19,7 @@ JWK = jose.JWKRSA(key=test_util.load_rsa_private_key(_KEY_BASE))
 IP_REGEX = re.compile(r"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$")
 
 
-def create_le_config(parent_dir):
+def create_le_config(parent_dir: str) -> argparse.Namespace:
     """Sets up LE dirs in parent_dir and returns the config dict"""
     config = copy.deepcopy(constants.CLI_DEFAULTS)
 
@@ -36,7 +36,7 @@ def create_le_config(parent_dir):
     return argparse.Namespace(**config)
 
 
-def extract_configs(configs, parent_dir):
+def extract_configs(configs: str, parent_dir: str) -> str:
     """Extracts configs to a new dir under parent_dir and returns it"""
     config_dir = os.path.join(parent_dir, "configs")
 
diff --git a/certbot-compatibility-test/certbot_compatibility_test/validator.py b/certbot-compatibility-test/certbot_compatibility_test/validator.py
index e2398ffbd..88dd06a67 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/validator.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/validator.py
@@ -2,7 +2,11 @@
 import logging
 import socket
 from typing import cast
+from typing import Mapping
+from typing import Optional
+from typing import Union
 
+from OpenSSL import crypto
 import requests
 
 from acme import crypto_util
@@ -14,10 +18,12 @@ logger = logging.getLogger(__name__)
 class Validator:
     """Collection of functions to test a live webserver's configuration"""
 
-    def certificate(self, cert, name, alt_host=None, port=443):
+    def certificate(self, cert: crypto.X509, name: Union[str, bytes],
+                    alt_host: Optional[str] = None, port: int = 443) -> bool:
         """Verifies the certificate presented at name is cert"""
         if alt_host is None:
-            host = socket.gethostbyname(name).encode()
+            # In fact, socket.gethostbyname accepts both bytes and str, but types do not know that.
+            host = socket.gethostbyname(cast(str, name)).encode()
         elif isinstance(alt_host, bytes):
             host = alt_host
         else:
@@ -31,9 +37,10 @@ class Validator:
             return False
 
         # Despite documentation saying that bytes are expected for digest(), we must provide a str.
-        return presented_cert.digest(cast(bytes, "sha256")) == cert.digest("sha256")
+        return presented_cert.digest(cast(bytes, "sha256")) == cert.digest(cast(bytes, "sha256"))
 
-    def redirect(self, name, port=80, headers=None):
+    def redirect(self, name: str, port: int = 80,
+                 headers: Optional[Mapping[str, str]] = None) -> bool:
         """Test whether webserver redirects to secure connection."""
         url = "http://{0}:{1}".format(name, port)
         if headers:
@@ -54,7 +61,8 @@ class Validator:
 
         return True
 
-    def any_redirect(self, name, port=80, headers=None):
+    def any_redirect(self, name: str, port: int = 80,
+                     headers: Optional[Mapping[str, str]] = None) -> bool:
         """Test whether webserver redirects."""
         url = "http://{0}:{1}".format(name, port)
         if headers:
@@ -64,7 +72,7 @@ class Validator:
 
         return response.status_code in range(300, 309)
 
-    def hsts(self, name):
+    def hsts(self, name: str) -> bool:
         """Test for HTTP Strict Transport Security header"""
         headers = requests.get("https://" + name).headers
         hsts_header = headers.get("strict-transport-security")
@@ -93,6 +101,6 @@ class Validator:
 
         return True
 
-    def ocsp_stapling(self, name):
+    def ocsp_stapling(self, name: str) -> None:
         """Verify ocsp stapling for domain."""
         raise NotImplementedError()
diff --git a/certbot-compatibility-test/certbot_compatibility_test/validator_test.py b/certbot-compatibility-test/certbot_compatibility_test/validator_test.py
index 711d1b38e..1a2d4dfb5 100644
--- a/certbot-compatibility-test/certbot_compatibility_test/validator_test.py
+++ b/certbot-compatibility-test/certbot_compatibility_test/validator_test.py
@@ -1,122 +1,126 @@
 """Tests for certbot_compatibility_test.validator."""
+from typing import cast
+from typing import Mapping
+from typing import Optional
 import unittest
 from unittest import mock
 
-import OpenSSL
+from certbot_compatibility_test import validator
+from OpenSSL import crypto
 import requests
 
 from acme import errors as acme_errors
-from certbot_compatibility_test import validator
 
 
 class ValidatorTest(unittest.TestCase):
-    def setUp(self):
+    def setUp(self) -> None:
         self.validator = validator.Validator()
 
     @mock.patch(
         "certbot_compatibility_test.validator.crypto_util.probe_sni")
-    def test_certificate_success(self, mock_probe_sni):
-        cert = OpenSSL.crypto.X509()
+    def test_certificate_success(self, mock_probe_sni: mock.MagicMock) -> None:
+        cert = crypto.X509()
         mock_probe_sni.return_value = cert
         self.assertTrue(self.validator.certificate(
             cert, "test.com", "127.0.0.1"))
 
     @mock.patch(
         "certbot_compatibility_test.validator.crypto_util.probe_sni")
-    def test_certificate_error(self, mock_probe_sni):
-        cert = OpenSSL.crypto.X509()
+    def test_certificate_error(self, mock_probe_sni: mock.MagicMock) -> None:
+        cert = crypto.X509()
         mock_probe_sni.side_effect = [acme_errors.Error]
         self.assertFalse(self.validator.certificate(
             cert, "test.com", "127.0.0.1"))
 
     @mock.patch(
         "certbot_compatibility_test.validator.crypto_util.probe_sni")
-    def test_certificate_failure(self, mock_probe_sni):
-        cert = OpenSSL.crypto.X509()
+    def test_certificate_failure(self, mock_probe_sni: mock.MagicMock) -> None:
+        cert = crypto.X509()
         cert.set_serial_number(1337)
-        mock_probe_sni.return_value = OpenSSL.crypto.X509()
+        mock_probe_sni.return_value = crypto.X509()
         self.assertFalse(self.validator.certificate(
             cert, "test.com", "127.0.0.1"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_successful_redirect(self, mock_get_request):
+    def test_successful_redirect(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             301, {"location": "https://test.com"})
         self.assertTrue(self.validator.redirect("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_redirect_with_headers(self, mock_get_request):
+    def test_redirect_with_headers(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             301, {"location": "https://test.com"})
         self.assertTrue(self.validator.redirect(
             "test.com", headers={"Host": "test.com"}))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_redirect_missing_location(self, mock_get_request):
+    def test_redirect_missing_location(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(301)
         self.assertFalse(self.validator.redirect("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_redirect_wrong_status_code(self, mock_get_request):
+    def test_redirect_wrong_status_code(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             201, {"location": "https://test.com"})
         self.assertFalse(self.validator.redirect("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_redirect_wrong_redirect_code(self, mock_get_request):
+    def test_redirect_wrong_redirect_code(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             303, {"location": "https://test.com"})
         self.assertFalse(self.validator.redirect("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts_empty(self, mock_get_request):
+    def test_hsts_empty(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security": ""})
         self.assertFalse(self.validator.hsts("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts_malformed(self, mock_get_request):
+    def test_hsts_malformed(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security": "sdfal"})
         self.assertFalse(self.validator.hsts("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts_bad_max_age(self, mock_get_request):
+    def test_hsts_bad_max_age(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security": "max-age=not-an-int"})
         self.assertFalse(self.validator.hsts("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts_expire(self, mock_get_request):
+    def test_hsts_expire(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security": "max-age=3600"})
         self.assertFalse(self.validator.hsts("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts(self, mock_get_request):
+    def test_hsts(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security": "max-age=31536000"})
         self.assertTrue(self.validator.hsts("test.com"))
 
     @mock.patch("certbot_compatibility_test.validator.requests.get")
-    def test_hsts_include_subdomains(self, mock_get_request):
+    def test_hsts_include_subdomains(self, mock_get_request: mock.MagicMock) -> None:
         mock_get_request.return_value = create_response(
             headers={"strict-transport-security":
                      "max-age=31536000;includeSubDomains"})
         self.assertTrue(self.validator.hsts("test.com"))
 
-    def test_ocsp_stapling(self):
+    def test_ocsp_stapling(self) -> None:
         self.assertRaises(
             NotImplementedError, self.validator.ocsp_stapling, "test.com")
 
 
-def create_response(status_code=200, headers=None):
+def create_response(status_code: int = 200,
+                    headers: Optional[Mapping[str, str]] = None) -> requests.Response:
     """Creates a requests.Response object for testing"""
     response = requests.Response()
     response.status_code = status_code
 
     if headers:
-        response.headers = headers
+        response.headers = cast(requests.models.CaseInsensitiveDict, headers)
 
     return response
 
diff --git a/tox.ini b/tox.ini
index 8ffd360b2..fe3ea5d9f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,8 +20,8 @@ install_and_test = python {toxinidir}/tools/install_and_test.py
 dns_packages = certbot-dns-cloudflare certbot-dns-cloudxns certbot-dns-digitalocean certbot-dns-dnsimple certbot-dns-dnsmadeeasy certbot-dns-gehirn certbot-dns-google certbot-dns-linode certbot-dns-luadns certbot-dns-nsone certbot-dns-ovh certbot-dns-rfc2136 certbot-dns-route53 certbot-dns-sakuracloud
 win_all_packages = acme[test] certbot[test] {[base]dns_packages} certbot-nginx
 all_packages = {[base]win_all_packages} certbot-apache
-fully_typed_source_paths = acme/acme certbot/certbot certbot-ci/certbot_integration_tests certbot-ci/snap_integration_tests certbot-ci/windows_installer_integration_tests tests/lock_test.py
-partially_typed_source_paths = certbot-apache/certbot_apache certbot-compatibility-test/certbot_compatibility_test certbot-dns-cloudflare/certbot_dns_cloudflare certbot-dns-cloudxns/certbot_dns_cloudxns certbot-dns-digitalocean/certbot_dns_digitalocean certbot-dns-dnsimple/certbot_dns_dnsimple certbot-dns-dnsmadeeasy/certbot_dns_dnsmadeeasy certbot-dns-gehirn/certbot_dns_gehirn certbot-dns-google/certbot_dns_google certbot-dns-linode/certbot_dns_linode certbot-dns-luadns/certbot_dns_luadns certbot-dns-nsone/certbot_dns_nsone certbot-dns-ovh/certbot_dns_ovh certbot-dns-rfc2136/certbot_dns_rfc2136 certbot-dns-route53/certbot_dns_route53 certbot-dns-sakuracloud/certbot_dns_sakuracloud certbot-nginx/certbot_nginx
+fully_typed_source_paths = acme/acme certbot/certbot certbot-ci/certbot_integration_tests certbot-ci/snap_integration_tests certbot-ci/windows_installer_integration_tests certbot-compatibility-test/certbot_compatibility_test tests/lock_test.py
+partially_typed_source_paths = certbot-apache/certbot_apache certbot-dns-cloudflare/certbot_dns_cloudflare certbot-dns-cloudxns/certbot_dns_cloudxns certbot-dns-digitalocean/certbot_dns_digitalocean certbot-dns-dnsimple/certbot_dns_dnsimple certbot-dns-dnsmadeeasy/certbot_dns_dnsmadeeasy certbot-dns-gehirn/certbot_dns_gehirn certbot-dns-google/certbot_dns_google certbot-dns-linode/certbot_dns_linode certbot-dns-luadns/certbot_dns_luadns certbot-dns-nsone/certbot_dns_nsone certbot-dns-ovh/certbot_dns_ovh certbot-dns-rfc2136/certbot_dns_rfc2136 certbot-dns-route53/certbot_dns_route53 certbot-dns-sakuracloud/certbot_dns_sakuracloud certbot-nginx/certbot_nginx
 
 [testenv]
 passenv =