diff --git a/django/apps/config.py b/django/apps/config.py
index 4845557051..157fda7238 100644
--- a/django/apps/config.py
+++ b/django/apps/config.py
@@ -8,15 +8,13 @@ MODELS_MODULE_NAME = 'models'
 
 
 class AppConfig:
-    """
-    Class representing a Django application and its configuration.
-    """
+    """Class representing a Django application and its configuration."""
 
     def __init__(self, app_name, app_module):
-        # Full Python path to the application eg. 'django.contrib.admin'.
+        # Full Python path to the application e.g. 'django.contrib.admin'.
         self.name = app_name
 
-        # Root module for the application eg. <module 'django.contrib.admin'
+        # Root module for the application e.g. <module 'django.contrib.admin'
         # from 'django/contrib/admin/__init__.py'>.
         self.module = app_module
 
@@ -27,21 +25,21 @@ class AppConfig:
         # The following attributes could be defined at the class level in a
         # subclass, hence the test-and-set pattern.
 
-        # Last component of the Python path to the application eg. 'admin'.
+        # Last component of the Python path to the application e.g. 'admin'.
         # This value must be unique across a Django project.
         if not hasattr(self, 'label'):
             self.label = app_name.rpartition(".")[2]
 
-        # Human-readable name for the application eg. "Admin".
+        # Human-readable name for the application e.g. "Admin".
         if not hasattr(self, 'verbose_name'):
             self.verbose_name = self.label.title()
 
-        # Filesystem path to the application directory eg.
+        # Filesystem path to the application directory e.g.
         # '/path/to/django/contrib/admin'.
         if not hasattr(self, 'path'):
             self.path = self._path_from_module(app_module)
 
-        # Module containing models eg. <module 'django.contrib.admin.models'
+        # Module containing models e.g. <module 'django.contrib.admin.models'
         # from 'django/contrib/admin/models.py'>. Set by import_models().
         # None if the application doesn't have a models module.
         self.models_module = None
@@ -155,9 +153,9 @@ class AppConfig:
 
     def get_model(self, model_name, require_ready=True):
         """
-        Returns the model with the given case-insensitive model_name.
+        Return the model with the given case-insensitive model_name.
 
-        Raises LookupError if no model exists with this name.
+        Raise LookupError if no model exists with this name.
         """
         if require_ready:
             self.apps.check_models_ready()
@@ -171,7 +169,7 @@ class AppConfig:
 
     def get_models(self, include_auto_created=False, include_swapped=False):
         """
-        Returns an iterable of models.
+        Return an iterable of models.
 
         By default, the following models aren't included:
 
diff --git a/django/apps/registry.py b/django/apps/registry.py
index 2c14ab627d..aff58db1c4 100644
--- a/django/apps/registry.py
+++ b/django/apps/registry.py
@@ -14,7 +14,7 @@ class Apps:
     """
     A registry that stores the configuration of installed applications.
 
-    It also keeps track of models eg. to provide reverse-relations.
+    It also keeps track of models, e.g. to provide reverse relations.
     """
 
     def __init__(self, installed_apps=()):
@@ -58,11 +58,11 @@ class Apps:
 
     def populate(self, installed_apps=None):
         """
-        Loads application configurations and models.
+        Load application configurations and models.
 
-        This method imports each application module and then each model module.
+        Import each application module and then each model module.
 
-        It is thread safe and idempotent, but not reentrant.
+        It is thread-safe and idempotent, but not reentrant.
         """
         if self.ready:
             return
@@ -122,31 +122,25 @@ class Apps:
             self.ready = True
 
     def check_apps_ready(self):
-        """
-        Raises an exception if all apps haven't been imported yet.
-        """
+        """Raise an exception if all apps haven't been imported yet."""
         if not self.apps_ready:
             raise AppRegistryNotReady("Apps aren't loaded yet.")
 
     def check_models_ready(self):
-        """
-        Raises an exception if all models haven't been imported yet.
-        """
+        """Raise an exception if all models haven't been imported yet."""
         if not self.models_ready:
             raise AppRegistryNotReady("Models aren't loaded yet.")
 
     def get_app_configs(self):
-        """
-        Imports applications and returns an iterable of app configs.
-        """
+        """Import applications and return an iterable of app configs."""
         self.check_apps_ready()
         return self.app_configs.values()
 
     def get_app_config(self, app_label):
         """
-        Imports applications and returns an app config for the given label.
+        Import applications and returns an app config for the given label.
 
-        Raises LookupError if no application exists with this label.
+        Raise LookupError if no application exists with this label.
         """
         self.check_apps_ready()
         try:
@@ -163,7 +157,7 @@ class Apps:
     @functools.lru_cache(maxsize=None)
     def get_models(self, include_auto_created=False, include_swapped=False):
         """
-        Returns a list of all installed models.
+        Return a list of all installed models.
 
         By default, the following models aren't included:
 
@@ -182,15 +176,14 @@ class Apps:
 
     def get_model(self, app_label, model_name=None, require_ready=True):
         """
-        Returns the model matching the given app_label and model_name.
+        Return the model matching the given app_label and model_name.
 
-        As a shortcut, this function also accepts a single argument in the
-        form <app_label>.<model_name>.
+        As a shortcut, app_label may be in the form <app_label>.<model_name>.
 
         model_name is case-insensitive.
 
-        Raises LookupError if no application exists with this label, or no
-        model exists with this name in the application. Raises ValueError if
+        Raise LookupError if no application exists with this label, or no
+        model exists with this name in the application. Raise ValueError if
         called with a single argument that doesn't contain exactly one dot.
         """
         if require_ready:
@@ -232,9 +225,9 @@ class Apps:
 
     def is_installed(self, app_name):
         """
-        Checks whether an application with this name exists in the registry.
+        Check whether an application with this name exists in the registry.
 
-        app_name is the full name of the app eg. 'django.contrib.admin'.
+        app_name is the full name of the app e.g. 'django.contrib.admin'.
         """
         self.check_apps_ready()
         return any(ac.name == app_name for ac in self.app_configs.values())
@@ -245,8 +238,8 @@ class Apps:
 
         object_name is the dotted Python path to the object.
 
-        Returns the app config for the inner application in case of nesting.
-        Returns None if the object isn't in any registered app config.
+        Return the app config for the inner application in case of nesting.
+        Return None if the object isn't in any registered app config.
         """
         self.check_apps_ready()
         candidates = []
@@ -296,7 +289,7 @@ class Apps:
 
     def set_available_apps(self, available):
         """
-        Restricts the set of installed apps used by get_app_config[s].
+        Restrict the set of installed apps used by get_app_config[s].
 
         available must be an iterable of application names.
 
@@ -304,7 +297,7 @@ class Apps:
 
         Primarily used for performance optimization in TransactionTestCase.
 
-        This method is safe is the sense that it doesn't trigger any imports.
+        This method is safe in the sense that it doesn't trigger any imports.
         """
         available = set(available)
         installed = set(app_config.name for app_config in self.get_app_configs())
@@ -322,15 +315,13 @@ class Apps:
         self.clear_cache()
 
     def unset_available_apps(self):
-        """
-        Cancels a previous call to set_available_apps().
-        """
+        """Cancel a previous call to set_available_apps()."""
         self.app_configs = self.stored_app_configs.pop()
         self.clear_cache()
 
     def set_installed_apps(self, installed):
         """
-        Enables a different set of installed apps for get_app_config[s].
+        Enable a different set of installed apps for get_app_config[s].
 
         installed must be an iterable in the same format as INSTALLED_APPS.
 
@@ -342,7 +333,7 @@ class Apps:
         This method may trigger new imports, which may add new models to the
         registry of all imported models. They will stay in the registry even
         after unset_installed_apps(). Since it isn't possible to replay
-        imports safely (eg. that could lead to registering listeners twice),
+        imports safely (e.g. that could lead to registering listeners twice),
         models are registered when they're imported and never removed.
         """
         if not self.ready:
@@ -354,16 +345,14 @@ class Apps:
         self.populate(installed)
 
     def unset_installed_apps(self):
-        """
-        Cancels a previous call to set_installed_apps().
-        """
+        """Cancel a previous call to set_installed_apps()."""
         self.app_configs = self.stored_app_configs.pop()
         self.apps_ready = self.models_ready = self.ready = True
         self.clear_cache()
 
     def clear_cache(self):
         """
-        Clears all internal caches, for methods that alter the app registry.
+        Clear all internal caches, for methods that alter the app registry.
 
         This is mostly used in tests.
         """
@@ -419,7 +408,7 @@ class Apps:
     def do_pending_operations(self, model):
         """
         Take a newly-prepared model and pass it to each function waiting for
-        it. This is called at the very end of `Apps.register_model()`.
+        it. This is called at the very end of Apps.register_model().
         """
         key = model._meta.app_label, model._meta.model_name
         for function in self._pending_operations.pop(key, []):
diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index 1d90d6fc0a..795f563085 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -1,9 +1,9 @@
 """
 Settings and configuration for Django.
 
-Values will be read from the module specified by the DJANGO_SETTINGS_MODULE environment
-variable, and then from django.conf.global_settings; see the global settings file for
-a list of all possible variables.
+Read values from the module specified by the DJANGO_SETTINGS_MODULE environment
+variable, and then from django.conf.global_settings; see the global_settings.py
+for a list of all possible variables.
 """
 
 import importlib
@@ -28,8 +28,8 @@ class LazySettings(LazyObject):
     def _setup(self, name=None):
         """
         Load the settings module pointed to by the environment variable. This
-        is used the first time we need any settings at all, if the user has not
-        previously configured the settings manually.
+        is used the first time settings are needed, if the user hasn't
+        configured settings manually.
         """
         settings_module = os.environ.get(ENVIRONMENT_VARIABLE)
         if not settings_module:
@@ -51,9 +51,7 @@ class LazySettings(LazyObject):
         }
 
     def __getattr__(self, name):
-        """
-        Return the value of a setting and cache it in self.__dict__.
-        """
+        """Return the value of a setting and cache it in self.__dict__."""
         if self._wrapped is empty:
             self._setup(name)
         val = getattr(self._wrapped, name)
@@ -72,9 +70,7 @@ class LazySettings(LazyObject):
         super().__setattr__(name, value)
 
     def __delattr__(self, name):
-        """
-        Delete a setting and clear it from cache if needed.
-        """
+        """Delete a setting and clear it from cache if needed."""
         super().__delattr__(name)
         self.__dict__.pop(name, None)
 
@@ -93,9 +89,7 @@ class LazySettings(LazyObject):
 
     @property
     def configured(self):
-        """
-        Returns True if the settings have already been configured.
-        """
+        """Return True if the settings have already been configured."""
         return self._wrapped is not empty
 
 
@@ -156,9 +150,7 @@ class Settings:
 
 
 class UserSettingsHolder:
-    """
-    Holder for user configured settings.
-    """
+    """Holder for user configured settings."""
     # SETTINGS_MODULE doesn't make much sense in the manually configured
     # (standalone) case.
     SETTINGS_MODULE = None
diff --git a/django/conf/urls/i18n.py b/django/conf/urls/i18n.py
index 3731afc886..70d99b4f29 100644
--- a/django/conf/urls/i18n.py
+++ b/django/conf/urls/i18n.py
@@ -8,9 +8,8 @@ from django.views.i18n import set_language
 
 def i18n_patterns(*urls, prefix_default_language=True):
     """
-    Adds the language code prefix to every URL pattern within this
-    function. This may only be used in the root URLconf, not in an included
-    URLconf.
+    Add the language code prefix to every URL pattern within this function.
+    This may only be used in the root URLconf, not in an included URLconf.
     """
     if not settings.USE_I18N:
         return list(urls)
diff --git a/django/conf/urls/static.py b/django/conf/urls/static.py
index be5da4924b..216602229f 100644
--- a/django/conf/urls/static.py
+++ b/django/conf/urls/static.py
@@ -8,7 +8,7 @@ from django.views.static import serve
 
 def static(prefix, view=serve, **kwargs):
     """
-    Helper function to return a URL pattern for serving files in debug mode.
+    Return a URL pattern for serving files in debug mode.
 
     from django.conf import settings
     from django.conf.urls.static import static
diff --git a/django/contrib/sessions/backends/signed_cookies.py b/django/contrib/sessions/backends/signed_cookies.py
index 7f1bd6a590..6391b3ef3e 100644
--- a/django/contrib/sessions/backends/signed_cookies.py
+++ b/django/contrib/sessions/backends/signed_cookies.py
@@ -7,9 +7,9 @@ class SessionStore(SessionBase):
 
     def load(self):
         """
-        We load the data from the key itself instead of fetching from
-        some external data store. Opposite of _get_session_key(),
-        raises BadSignature if signature fails.
+        Load the data from the key itself instead of fetching from some
+        external data store. Opposite of _get_session_key(), raise BadSignature
+        if signature fails.
         """
         try:
             return signing.loads(
diff --git a/django/middleware/cache.py b/django/middleware/cache.py
index a4dde10dc4..8af0c9db7c 100644
--- a/django/middleware/cache.py
+++ b/django/middleware/cache.py
@@ -72,7 +72,7 @@ class UpdateCacheMiddleware(MiddlewareMixin):
         return hasattr(request, '_cache_update_cache') and request._cache_update_cache
 
     def process_response(self, request, response):
-        """Sets the cache, if needed."""
+        """Set the cache, if needed."""
         if not self._should_update_cache(request, response):
             # We don't need to update the cache, just return.
             return response
@@ -122,7 +122,7 @@ class FetchFromCacheMiddleware(MiddlewareMixin):
 
     def process_request(self, request):
         """
-        Checks whether the page is already cached and returns the cached
+        Check whether the page is already cached and return the cached
         version if available.
         """
         if request.method not in ('GET', 'HEAD'):
diff --git a/django/middleware/clickjacking.py b/django/middleware/clickjacking.py
index 8659646c61..a0506142b9 100644
--- a/django/middleware/clickjacking.py
+++ b/django/middleware/clickjacking.py
@@ -11,21 +11,15 @@ from django.utils.deprecation import MiddlewareMixin
 
 class XFrameOptionsMiddleware(MiddlewareMixin):
     """
-    Middleware that sets the X-Frame-Options HTTP header in HTTP responses.
+    Set the X-Frame-Options HTTP header in HTTP responses.
 
-    Does not set the header if it's already set or if the response contains
+    Do not set the header if it's already set or if the response contains
     a xframe_options_exempt value set to True.
 
-    By default, sets the X-Frame-Options header to 'SAMEORIGIN', meaning the
+    By default, set the X-Frame-Options header to 'SAMEORIGIN', meaning the
     response can only be loaded on a frame within the same site. To prevent the
     response from being loaded in a frame in any site, set X_FRAME_OPTIONS in
     your project's Django settings to 'DENY'.
-
-    Note: older browsers will quietly ignore this header, thus other
-    clickjacking protection techniques should be used if protection in those
-    browsers is required.
-
-    https://en.wikipedia.org/wiki/Clickjacking#Server_and_client
     """
     def process_response(self, request, response):
         # Don't set it if it's already in the response
@@ -42,10 +36,8 @@ class XFrameOptionsMiddleware(MiddlewareMixin):
 
     def get_xframe_options_value(self, request, response):
         """
-        Gets the value to set for the X_FRAME_OPTIONS header.
-
-        By default this uses the value from the X_FRAME_OPTIONS Django
-        settings. If not found in settings, defaults to 'SAMEORIGIN'.
+        Get the value to set for the X_FRAME_OPTIONS header. Use the value from
+        the X_FRAME_OPTIONS setting, or 'SAMEORIGIN' if not set.
 
         This method can be overridden if needed, allowing it to vary based on
         the request or response.
diff --git a/django/middleware/common.py b/django/middleware/common.py
index cab5279a73..d8cfb9a8b0 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -17,17 +17,16 @@ class CommonMiddleware(MiddlewareMixin):
     """
     "Common" middleware for taking care of some basic operations:
 
-        - Forbids access to User-Agents in settings.DISALLOWED_USER_AGENTS
+        - Forbid access to User-Agents in settings.DISALLOWED_USER_AGENTS
 
         - URL rewriting: Based on the APPEND_SLASH and PREPEND_WWW settings,
-          this middleware appends missing slashes and/or prepends missing
-          "www."s.
+          append missing slashes and/or prepends missing "www."s.
 
             - If APPEND_SLASH is set and the initial URL doesn't end with a
-              slash, and it is not found in urlpatterns, a new URL is formed by
+              slash, and it is not found in urlpatterns, form a new URL by
               appending a slash at the end. If this new URL is found in
-              urlpatterns, then an HTTP-redirect is returned to this new URL;
-              otherwise the initial URL is processed as usual.
+              urlpatterns, return an HTTP redirect to this new URL; otherwise
+              process the initial URL as usual.
 
           This behavior can be customized by subclassing CommonMiddleware and
           overriding the response_redirect_class attribute.
@@ -140,9 +139,7 @@ class CommonMiddleware(MiddlewareMixin):
         return response
 
     def needs_etag(self, response):
-        """
-        Return True if an ETag header should be added to response.
-        """
+        """Return True if an ETag header should be added to response."""
         cache_control_headers = cc_delim_re.split(response.get('Cache-Control', ''))
         return all(header.lower() != 'no-store' for header in cache_control_headers)
 
@@ -150,9 +147,7 @@ class CommonMiddleware(MiddlewareMixin):
 class BrokenLinkEmailsMiddleware(MiddlewareMixin):
 
     def process_response(self, request, response):
-        """
-        Send broken link emails for relevant 404 NOT FOUND responses.
-        """
+        """Send broken link emails for relevant 404 NOT FOUND responses."""
         if response.status_code == 404 and not settings.DEBUG:
             domain = request.get_host()
             path = request.get_full_path()
@@ -173,7 +168,8 @@ class BrokenLinkEmailsMiddleware(MiddlewareMixin):
 
     def is_internal_request(self, domain, referer):
         """
-        Returns True if the referring URL is the same domain as the current request.
+        Return True if the referring URL is the same domain as the current
+        request.
         """
         # Different subdomains are treated as different domains.
         return bool(re.match("^https?://%s/" % re.escape(domain), referer))
diff --git a/django/middleware/csrf.py b/django/middleware/csrf.py
index 44fe892229..027d0d0b29 100644
--- a/django/middleware/csrf.py
+++ b/django/middleware/csrf.py
@@ -33,9 +33,7 @@ CSRF_SESSION_KEY = '_csrftoken'
 
 
 def _get_failure_view():
-    """
-    Returns the view to be used for CSRF rejections
-    """
+    """Return the view to be used for CSRF rejections."""
     return get_callable(settings.CSRF_FAILURE_VIEW)
 
 
@@ -75,7 +73,7 @@ def _get_new_csrf_token():
 
 def get_token(request):
     """
-    Returns the CSRF token required for a POST form. The token is an
+    Return the CSRF token required for a POST form. The token is an
     alphanumeric value. A new token is created if one is not already set.
 
     A side effect of calling this function is to make the csrf_protect
@@ -94,7 +92,7 @@ def get_token(request):
 
 def rotate_token(request):
     """
-    Changes the CSRF token in use for a request - should be done on login
+    Change the CSRF token in use for a request - should be done on login
     for security purposes.
     """
     request.META.update({
@@ -132,12 +130,11 @@ def _compare_salted_tokens(request_csrf_token, csrf_token):
 
 class CsrfViewMiddleware(MiddlewareMixin):
     """
-    Middleware that requires a present and correct csrfmiddlewaretoken
-    for POST requests that have a CSRF cookie, and sets an outgoing
-    CSRF cookie.
+    Require a present and correct csrfmiddlewaretoken for POST requests that
+    have a CSRF cookie, and set an outgoing CSRF cookie.
 
-    This middleware should be used in conjunction with the csrf_token template
-    tag.
+    This middleware should be used in conjunction with the {% csrf_token %}
+    template tag.
     """
     # The _accept and _reject methods currently only exist for the sake of the
     # requires_csrf_token decorator.
diff --git a/django/middleware/gzip.py b/django/middleware/gzip.py
index d6e2134f17..0c3905c959 100644
--- a/django/middleware/gzip.py
+++ b/django/middleware/gzip.py
@@ -9,8 +9,8 @@ re_accepts_gzip = re.compile(r'\bgzip\b')
 
 class GZipMiddleware(MiddlewareMixin):
     """
-    This middleware compresses content if the browser allows gzip compression.
-    It sets the Vary header accordingly, so that caches will base their storage
+    Compress content if the browser allows gzip compression.
+    Set the Vary header accordingly, so that caches will base their storage
     on the Accept-Encoding header.
     """
     def process_response(self, request, response):
diff --git a/django/middleware/http.py b/django/middleware/http.py
index 173bb49f89..a739597f91 100644
--- a/django/middleware/http.py
+++ b/django/middleware/http.py
@@ -7,10 +7,9 @@ from django.utils.http import parse_http_date_safe
 
 class ConditionalGetMiddleware(MiddlewareMixin):
     """
-    Handles conditional GET operations. If the response has an ETag or
-    Last-Modified header, and the request has If-None-Match or
-    If-Modified-Since, the response is replaced by an HttpNotModified. An ETag
-    header is added if needed.
+    Handle conditional GET operations. If the response has an ETag or
+    Last-Modified header and the request has If-None-Match or If-Modified-Since,
+    replace the response with HttpNotModified. Add an ETag header if needed.
     """
     def process_response(self, request, response):
         # It's too late to prevent an unsafe request with a 412 response, and
@@ -38,8 +37,6 @@ class ConditionalGetMiddleware(MiddlewareMixin):
         return response
 
     def needs_etag(self, response):
-        """
-        Return True if an ETag header should be added to response.
-        """
+        """Return True if an ETag header should be added to response."""
         cache_control_headers = cc_delim_re.split(response.get('Cache-Control', ''))
         return all(header.lower() != 'no-store' for header in cache_control_headers)
diff --git a/django/middleware/locale.py b/django/middleware/locale.py
index 5643e484c6..ee057786ee 100644
--- a/django/middleware/locale.py
+++ b/django/middleware/locale.py
@@ -1,5 +1,3 @@
-"This is the locale selecting middleware that will look at accept headers"
-
 from django.conf import settings
 from django.conf.urls.i18n import is_language_prefix_patterns_used
 from django.http import HttpResponseRedirect
@@ -11,11 +9,9 @@ from django.utils.deprecation import MiddlewareMixin
 
 class LocaleMiddleware(MiddlewareMixin):
     """
-    This is a very simple middleware that parses a request
-    and decides what translation object to install in the current
-    thread context. This allows pages to be dynamically
-    translated to the language the user desires (if the language
-    is available, of course).
+    Parse a request and decide what translation object to install in the
+    current thread context. This allows pages to be dynamically translated to
+    the language the user desires (if the language is available, of course).
     """
     response_redirect_class = HttpResponseRedirect
 
diff --git a/django/shortcuts.py b/django/shortcuts.py
index c489ecd5cd..0ce7ee327f 100644
--- a/django/shortcuts.py
+++ b/django/shortcuts.py
@@ -17,7 +17,7 @@ from django.utils.functional import Promise
 
 def render_to_response(template_name, context=None, content_type=None, status=None, using=None):
     """
-    Returns a HttpResponse whose content is filled with the result of calling
+    Return a HttpResponse whose content is filled with the result of calling
     django.template.loader.render_to_string() with the passed arguments.
     """
     warnings.warn(
@@ -31,7 +31,7 @@ def render_to_response(template_name, context=None, content_type=None, status=No
 
 def render(request, template_name, context=None, content_type=None, status=None, using=None):
     """
-    Returns a HttpResponse whose content is filled with the result of calling
+    Return a HttpResponse whose content is filled with the result of calling
     django.template.loader.render_to_string() with the passed arguments.
     """
     content = loader.render_to_string(template_name, context, request, using=using)
@@ -40,7 +40,7 @@ def render(request, template_name, context=None, content_type=None, status=None,
 
 def redirect(to, *args, permanent=False, **kwargs):
     """
-    Returns an HttpResponseRedirect to the appropriate URL for the arguments
+    Return an HttpResponseRedirect to the appropriate URL for the arguments
     passed.
 
     The arguments could be:
@@ -74,7 +74,7 @@ def _get_queryset(klass):
 
 def get_object_or_404(klass, *args, **kwargs):
     """
-    Uses get() to return an object, or raises a Http404 exception if the object
+    Use get() to return an object, or raise a Http404 exception if the object
     does not exist.
 
     klass may be a Model, Manager, or QuerySet object. All other passed
@@ -98,7 +98,7 @@ def get_object_or_404(klass, *args, **kwargs):
 
 def get_list_or_404(klass, *args, **kwargs):
     """
-    Uses filter() to return a list of objects, or raise a Http404 exception if
+    Use filter() to return a list of objects, or raise a Http404 exception if
     the list is empty.
 
     klass may be a Model, Manager, or QuerySet object. All other passed
diff --git a/django/test/__init__.py b/django/test/__init__.py
index e3561f5ae7..4782d72184 100644
--- a/django/test/__init__.py
+++ b/django/test/__init__.py
@@ -1,6 +1,4 @@
-"""
-Django Unit Test and Doctest framework.
-"""
+"""Django Unit Test framework."""
 
 from django.test.client import Client, RequestFactory
 from django.test.testcases import (
diff --git a/django/test/client.py b/django/test/client.py
index 87b59af363..947a1fb56f 100644
--- a/django/test/client.py
+++ b/django/test/client.py
@@ -36,9 +36,7 @@ JSON_CONTENT_TYPE_RE = re.compile(r'^application\/(vnd\..+\+)?json$')
 
 
 class RedirectCycleError(Exception):
-    """
-    The test client has been asked to follow a redirect loop.
-    """
+    """The test client has been asked to follow a redirect loop."""
     def __init__(self, message, last_response):
         super().__init__(message)
         self.last_response = last_response
@@ -50,7 +48,7 @@ class FakePayload:
     A wrapper around BytesIO that restricts what can be read since data from
     the network can't be seeked and cannot be read outside of its content
     length. This makes sure that views can't do anything under the test client
-    that wouldn't work in Real Life.
+    that wouldn't work in real life.
     """
     def __init__(self, content=None):
         self.__content = BytesIO()
@@ -93,7 +91,7 @@ def closing_iterator_wrapper(iterable, close):
 def conditional_content_removal(request, response):
     """
     Simulate the behavior of most Web servers by removing the content of
-    responses for HEAD requests, 1xx, 204, and 304 responses. Ensures
+    responses for HEAD requests, 1xx, 204, and 304 responses. Ensure
     compliance with RFC 7230, section 3.3.3.
     """
     if 100 <= response.status_code < 200 or response.status_code in (204, 304):
@@ -112,8 +110,8 @@ def conditional_content_removal(request, response):
 
 class ClientHandler(BaseHandler):
     """
-    A HTTP Handler that can be used for testing purposes. Uses the WSGI
-    interface to compose requests, but returns the raw HttpResponse object with
+    A HTTP Handler that can be used for testing purposes. Use the WSGI
+    interface to compose requests, but return the raw HttpResponse object with
     the originating WSGIRequest attached to its ``wsgi_request`` attribute.
     """
     def __init__(self, enforce_csrf_checks=True, *args, **kwargs):
@@ -146,8 +144,7 @@ class ClientHandler(BaseHandler):
         # later retrieved.
         response.wsgi_request = request
 
-        # We're emulating a WSGI server; we must call the close method
-        # on completion.
+        # Emulate a WSGI server by calling the close method on completion.
         if response.streaming:
             response.streaming_content = closing_iterator_wrapper(
                 response.streaming_content, response.close)
@@ -161,7 +158,7 @@ class ClientHandler(BaseHandler):
 
 def store_rendered_templates(store, signal, sender, template, context, **kwargs):
     """
-    Stores templates and contexts that are rendered.
+    Store templates and contexts that are rendered.
 
     The context is copied so that it is an accurate representation at the time
     of rendering.
@@ -174,7 +171,7 @@ def store_rendered_templates(store, signal, sender, template, context, **kwargs)
 
 def encode_multipart(boundary, data):
     """
-    Encodes multipart POST data from a dictionary of form values.
+    Encode multipart POST data from a dictionary of form values.
 
     The key will be used as the form data name; the value will be transmitted
     as content. If the value is a file, the contents of the file will be sent
@@ -326,8 +323,7 @@ class RequestFactory:
         return path.decode('iso-8859-1')
 
     def get(self, path, data=None, secure=False, **extra):
-        "Construct a GET request."
-
+        """Construct a GET request."""
         data = {} if data is None else data
         r = {
             'QUERY_STRING': urlencode(data, doseq=True),
@@ -337,8 +333,7 @@ class RequestFactory:
 
     def post(self, path, data=None, content_type=MULTIPART_CONTENT,
              secure=False, **extra):
-        "Construct a POST request."
-
+        """Construct a POST request."""
         data = {} if data is None else data
         post_data = self._encode_data(data, content_type)
 
@@ -346,8 +341,7 @@ class RequestFactory:
                             secure=secure, **extra)
 
     def head(self, path, data=None, secure=False, **extra):
-        "Construct a HEAD request."
-
+        """Construct a HEAD request."""
         data = {} if data is None else data
         r = {
             'QUERY_STRING': urlencode(data, doseq=True),
@@ -356,7 +350,7 @@ class RequestFactory:
         return self.generic('HEAD', path, secure=secure, **r)
 
     def trace(self, path, secure=False, **extra):
-        "Construct a TRACE request."
+        """Construct a TRACE request."""
         return self.generic('TRACE', path, secure=secure, **extra)
 
     def options(self, path, data='', content_type='application/octet-stream',
@@ -367,26 +361,26 @@ class RequestFactory:
 
     def put(self, path, data='', content_type='application/octet-stream',
             secure=False, **extra):
-        "Construct a PUT request."
+        """Construct a PUT request."""
         return self.generic('PUT', path, data, content_type,
                             secure=secure, **extra)
 
     def patch(self, path, data='', content_type='application/octet-stream',
               secure=False, **extra):
-        "Construct a PATCH request."
+        """Construct a PATCH request."""
         return self.generic('PATCH', path, data, content_type,
                             secure=secure, **extra)
 
     def delete(self, path, data='', content_type='application/octet-stream',
                secure=False, **extra):
-        "Construct a DELETE request."
+        """Construct a DELETE request."""
         return self.generic('DELETE', path, data, content_type,
                             secure=secure, **extra)
 
     def generic(self, method, path, data='',
                 content_type='application/octet-stream', secure=False,
                 **extra):
-        """Constructs an arbitrary HTTP request."""
+        """Construct an arbitrary HTTP request."""
         parsed = urlparse(str(path))  # path can be lazy
         data = force_bytes(data, settings.DEFAULT_CHARSET)
         r = {
@@ -434,16 +428,12 @@ class Client(RequestFactory):
         self.exc_info = None
 
     def store_exc_info(self, **kwargs):
-        """
-        Stores exceptions when they are generated by a view.
-        """
+        """Store exceptions when they are generated by a view."""
         self.exc_info = sys.exc_info()
 
     @property
     def session(self):
-        """
-        Obtains the current session variables.
-        """
+        """Return the current session variables."""
         engine = import_module(settings.SESSION_ENGINE)
         cookie = self.cookies.get(settings.SESSION_COOKIE_NAME)
         if cookie:
@@ -456,10 +446,10 @@ class Client(RequestFactory):
 
     def request(self, **request):
         """
-        The master request method. Composes the environment dictionary
-        and passes to the handler, returning the result of the handler.
-        Assumes defaults for the query environment, which can be overridden
-        using the arguments to the request.
+        The master request method. Compose the environment dictionary and pass
+        to the handler, return the result of the handler. Assume defaults for
+        the query environment, which can be overridden using the arguments to
+        the request.
         """
         environ = self._base_environ(**request)
 
@@ -523,9 +513,7 @@ class Client(RequestFactory):
             got_request_exception.disconnect(dispatch_uid=exception_uid)
 
     def get(self, path, data=None, follow=False, secure=False, **extra):
-        """
-        Requests a response from the server using GET.
-        """
+        """Request a response from the server using GET."""
         response = super().get(path, data=data, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -533,18 +521,14 @@ class Client(RequestFactory):
 
     def post(self, path, data=None, content_type=MULTIPART_CONTENT,
              follow=False, secure=False, **extra):
-        """
-        Requests a response from the server using POST.
-        """
+        """Request a response from the server using POST."""
         response = super().post(path, data=data, content_type=content_type, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
         return response
 
     def head(self, path, data=None, follow=False, secure=False, **extra):
-        """
-        Request a response from the server using HEAD.
-        """
+        """Request a response from the server using HEAD."""
         response = super().head(path, data=data, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -552,9 +536,7 @@ class Client(RequestFactory):
 
     def options(self, path, data='', content_type='application/octet-stream',
                 follow=False, secure=False, **extra):
-        """
-        Request a response from the server using OPTIONS.
-        """
+        """Request a response from the server using OPTIONS."""
         response = super().options(path, data=data, content_type=content_type, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -562,9 +544,7 @@ class Client(RequestFactory):
 
     def put(self, path, data='', content_type='application/octet-stream',
             follow=False, secure=False, **extra):
-        """
-        Send a resource to the server using PUT.
-        """
+        """Send a resource to the server using PUT."""
         response = super().put(path, data=data, content_type=content_type, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -572,9 +552,7 @@ class Client(RequestFactory):
 
     def patch(self, path, data='', content_type='application/octet-stream',
               follow=False, secure=False, **extra):
-        """
-        Send a resource to the server using PATCH.
-        """
+        """Send a resource to the server using PATCH."""
         response = super().patch(path, data=data, content_type=content_type, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -582,18 +560,14 @@ class Client(RequestFactory):
 
     def delete(self, path, data='', content_type='application/octet-stream',
                follow=False, secure=False, **extra):
-        """
-        Send a DELETE request to the server.
-        """
+        """Send a DELETE request to the server."""
         response = super().delete(path, data=data, content_type=content_type, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
         return response
 
     def trace(self, path, data='', follow=False, secure=False, **extra):
-        """
-        Send a TRACE request to the server.
-        """
+        """Send a TRACE request to the server."""
         response = super().trace(path, data=data, secure=secure, **extra)
         if follow:
             response = self._handle_redirects(response, **extra)
@@ -601,9 +575,9 @@ class Client(RequestFactory):
 
     def login(self, **credentials):
         """
-        Sets the Factory to appear as if it has successfully logged into a site.
+        Set the Factory to appear as if it has successfully logged into a site.
 
-        Returns True if login is possible; False if the provided credentials
+        Return True if login is possible; False if the provided credentials
         are incorrect.
         """
         from django.contrib.auth import authenticate
@@ -655,11 +629,7 @@ class Client(RequestFactory):
         self.cookies[session_cookie].update(cookie_data)
 
     def logout(self):
-        """
-        Removes the authenticated user's cookies and session object.
-
-        Causes the authenticated user to be logged out.
-        """
+        """Log out the user by removing the cookies and session object."""
         from django.contrib.auth import get_user, logout
 
         request = HttpRequest()
@@ -683,8 +653,9 @@ class Client(RequestFactory):
         return response._json
 
     def _handle_redirects(self, response, **extra):
-        "Follows any redirects by requesting responses from the server using GET."
-
+        """
+        Follow any redirects by requesting responses from the server using GET.
+        """
         response.redirect_chain = []
         while response.status_code in (301, 302, 303, 307):
             response_url = response.url
diff --git a/django/test/html.py b/django/test/html.py
index 900aa3d3f0..726beb6e93 100644
--- a/django/test/html.py
+++ b/django/test/html.py
@@ -1,6 +1,4 @@
-"""
-Comparing two html documents.
-"""
+"""Compare two HTML documents."""
 
 import re
 
@@ -214,7 +212,7 @@ class Parser(HTMLParser):
 
 def parse_html(html):
     """
-    Takes a string that contains *valid* HTML and turns it into a Python object
+    Take a string that contains *valid* HTML and turn it into a Python object
     structure that can be easily compared against other HTML on semantic
     equivalence. Syntactical differences like which quotation is used on
     arguments will be ignored.
diff --git a/django/test/runner.py b/django/test/runner.py
index cb1893c56a..0255348854 100644
--- a/django/test/runner.py
+++ b/django/test/runner.py
@@ -253,9 +253,7 @@ class RemoteTestRunner:
 
 
 def default_test_processes():
-    """
-    Default number of test processes when using the --parallel option.
-    """
+    """Default number of test processes when using the --parallel option."""
     # The current implementation of the parallel test runner requires
     # multiprocessing to start subprocesses with fork().
     if multiprocessing.get_start_method() != 'fork':
@@ -389,9 +387,7 @@ class ParallelTestSuite(unittest.TestSuite):
 
 
 class DiscoverRunner:
-    """
-    A Django test runner that uses unittest2 test discovery.
-    """
+    """A Django test runner that uses unittest2 test discovery."""
 
     test_suite = unittest.TestSuite
     parallel_test_suite = ParallelTestSuite
@@ -566,9 +562,7 @@ class DiscoverRunner:
         return runner.run(suite)
 
     def teardown_databases(self, old_config, **kwargs):
-        """
-        Destroys all the non-mirror databases.
-        """
+        """Destroy all the non-mirror databases."""
         _teardown_databases(
             old_config,
             verbosity=self.verbosity,
@@ -593,7 +587,7 @@ class DiscoverRunner:
         A list of 'extra' tests may also be provided; these tests
         will be added to the test suite.
 
-        Returns the number of tests that failed.
+        Return the number of tests that failed.
         """
         self.setup_test_environment()
         suite = self.build_suite(test_labels, extra_tests)
@@ -623,15 +617,15 @@ def is_discoverable(label):
 
 def reorder_suite(suite, classes, reverse=False):
     """
-    Reorders a test suite by test type.
+    Reorder a test suite by test type.
 
     `classes` is a sequence of types
 
     All tests of type classes[0] are placed first, then tests of type
     classes[1], etc. Tests with no match in classes are placed last.
 
-    If `reverse` is True, tests within classes are sorted in opposite order,
-    but test classes are not reversed.
+    If `reverse` is True, sort tests within classes in opposite order but
+    don't reverse test classes.
     """
     class_count = len(classes)
     suite_class = type(suite)
@@ -645,7 +639,7 @@ def reorder_suite(suite, classes, reverse=False):
 
 def partition_suite_by_type(suite, classes, bins, reverse=False):
     """
-    Partitions a test suite by test type. Also prevents duplicated tests.
+    Partition a test suite by test type. Also prevent duplicated tests.
 
     classes is a sequence of types
     bins is a sequence of TestSuites, one more than classes
@@ -670,9 +664,7 @@ def partition_suite_by_type(suite, classes, bins, reverse=False):
 
 
 def partition_suite_by_case(suite):
-    """
-    Partitions a test suite by test case, preserving the order of tests.
-    """
+    """Partition a test suite by test case, preserving the order of tests."""
     groups = []
     suite_class = type(suite)
     for test_type, test_group in itertools.groupby(suite, type):
diff --git a/django/test/selenium.py b/django/test/selenium.py
index 2b14678b23..9bf1e1038d 100644
--- a/django/test/selenium.py
+++ b/django/test/selenium.py
@@ -73,7 +73,7 @@ class SeleniumTestCase(LiveServerTestCase, metaclass=SeleniumTestCaseBase):
 
     @contextmanager
     def disable_implicit_wait(self):
-        """Context manager that disables the default implicit wait."""
+        """Disable the default implicit wait."""
         self.selenium.implicitly_wait(0)
         try:
             yield
diff --git a/django/test/testcases.py b/django/test/testcases.py
index b8d57378de..4be5baf4b8 100644
--- a/django/test/testcases.py
+++ b/django/test/testcases.py
@@ -43,8 +43,8 @@ __all__ = ('TestCase', 'TransactionTestCase',
 
 def to_list(value):
     """
-    Puts value into a list if it's not already one.
-    Returns an empty list if value is None.
+    Put value into a list if it's not already one. Return an empty list if
+    value is None.
     """
     if value is None:
         value = []
@@ -212,21 +212,22 @@ class SimpleTestCase(unittest.TestCase):
                 return
 
     def _pre_setup(self):
-        """Performs any pre-test setup. This includes:
-
-        * Creating a test client.
-        * Clearing the mail test outbox.
+        """
+        Perform pre-test setup:
+        * Create a test client.
+        * Clear the mail test outbox.
         """
         self.client = self.client_class()
         mail.outbox = []
 
     def _post_teardown(self):
-        """Perform any post-test things."""
+        """Perform post-test things."""
         pass
 
     def settings(self, **kwargs):
         """
-        A context manager that temporarily sets a setting and reverts to the original value when exiting the context.
+        A context manager that temporarily sets a setting and reverts to the
+        original value when exiting the context.
         """
         return override_settings(**kwargs)
 
@@ -240,12 +241,13 @@ class SimpleTestCase(unittest.TestCase):
     def assertRedirects(self, response, expected_url, status_code=302,
                         target_status_code=200, msg_prefix='',
                         fetch_redirect_response=True):
-        """Asserts that a response redirected to a specific URL, and that the
+        """
+        Assert that a response redirected to a specific URL and that the
         redirect URL can be loaded.
 
-        Note that assertRedirects won't work for external links since it uses
-        TestClient to do a request (use fetch_redirect_response=False to check
-        such links without fetching them).
+        Won't work for external links since it uses TestClient to do a request
+        (use fetch_redirect_response=False to check such links without fetching
+        them).
         """
         if msg_prefix:
             msg_prefix += ": "
@@ -349,8 +351,8 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertContains(self, response, text, count=None, status_code=200, msg_prefix='', html=False):
         """
-        Asserts that a response indicates that some content was retrieved
-        successfully, (i.e., the HTTP status code was as expected), and that
+        Assert that a response indicates that some content was retrieved
+        successfully, (i.e., the HTTP status code was as expected) and that
         ``text`` occurs ``count`` times in the content of the response.
         If ``count`` is None, the count doesn't matter - the assertion is true
         if the text occurs at least once in the response.
@@ -368,8 +370,8 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertNotContains(self, response, text, status_code=200, msg_prefix='', html=False):
         """
-        Asserts that a response indicates that some content was retrieved
-        successfully, (i.e., the HTTP status code was as expected), and that
+        Assert that a response indicates that some content was retrieved
+        successfully, (i.e., the HTTP status code was as expected) and that
         ``text`` doesn't occurs in the content of the response.
         """
         text_repr, real_count, msg_prefix = self._assert_contains(
@@ -379,7 +381,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertFormError(self, response, form, field, errors, msg_prefix=''):
         """
-        Asserts that a form used to render the response has a specific field
+        Assert that a form used to render the response has a specific field
         error.
         """
         if msg_prefix:
@@ -435,7 +437,7 @@ class SimpleTestCase(unittest.TestCase):
     def assertFormsetError(self, response, formset, form_index, field, errors,
                            msg_prefix=''):
         """
-        Asserts that a formset used to render the response has a specific error.
+        Assert that a formset used to render the response has a specific error.
 
         For field errors, specify the ``form_index`` and the ``field``.
         For non-field errors, specify the ``form_index`` and the ``field`` as
@@ -538,7 +540,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertTemplateUsed(self, response=None, template_name=None, msg_prefix='', count=None):
         """
-        Asserts that the template with the provided name was used in rendering
+        Assert that the template with the provided name was used in rendering
         the response. Also usable as context manager.
         """
         context_mgr_template, template_names, msg_prefix = self._assert_template_used(
@@ -567,7 +569,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertTemplateNotUsed(self, response=None, template_name=None, msg_prefix=''):
         """
-        Asserts that the template with the provided name was NOT used in
+        Assert that the template with the provided name was NOT used in
         rendering the response. Also usable as context manager.
         """
         context_mgr_template, template_names, msg_prefix = self._assert_template_used(
@@ -590,7 +592,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertRaisesMessage(self, expected_exception, expected_message, *args, **kwargs):
         """
-        Asserts that expected_message is found in the the message of a raised
+        Assert that expected_message is found in the the message of a raised
         exception.
 
         Args:
@@ -615,7 +617,7 @@ class SimpleTestCase(unittest.TestCase):
     def assertFieldOutput(self, fieldclass, valid, invalid, field_args=None,
                           field_kwargs=None, empty_value=''):
         """
-        Asserts that a form field behaves correctly with various inputs.
+        Assert that a form field behaves correctly with various inputs.
 
         Args:
             fieldclass: the class of the field to be tested.
@@ -660,9 +662,9 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertHTMLEqual(self, html1, html2, msg=None):
         """
-        Asserts that two HTML snippets are semantically the same.
+        Assert that two HTML snippets are semantically the same.
         Whitespace in most cases is ignored, and attribute ordering is not
-        significant. The passed-in arguments must be valid HTML.
+        significant. The arguments must be valid HTML.
         """
         dom1 = assert_and_parse_html(self, html1, msg, 'First argument is not valid HTML:')
         dom2 = assert_and_parse_html(self, html2, msg, 'Second argument is not valid HTML:')
@@ -677,7 +679,7 @@ class SimpleTestCase(unittest.TestCase):
             self.fail(self._formatMessage(msg, standardMsg))
 
     def assertHTMLNotEqual(self, html1, html2, msg=None):
-        """Asserts that two HTML snippets are not semantically equivalent."""
+        """Assert that two HTML snippets are not semantically equivalent."""
         dom1 = assert_and_parse_html(self, html1, msg, 'First argument is not valid HTML:')
         dom2 = assert_and_parse_html(self, html2, msg, 'Second argument is not valid HTML:')
 
@@ -700,7 +702,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertJSONEqual(self, raw, expected_data, msg=None):
         """
-        Asserts that the JSON fragments raw and expected_data are equal.
+        Assert that the JSON fragments raw and expected_data are equal.
         Usual JSON non-significant whitespace rules apply as the heavyweight
         is delegated to the json library.
         """
@@ -717,7 +719,7 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertJSONNotEqual(self, raw, expected_data, msg=None):
         """
-        Asserts that the JSON fragments raw and expected_data are not equal.
+        Assert that the JSON fragments raw and expected_data are not equal.
         Usual JSON non-significant whitespace rules apply as the heavyweight
         is delegated to the json library.
         """
@@ -734,9 +736,9 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertXMLEqual(self, xml1, xml2, msg=None):
         """
-        Asserts that two XML snippets are semantically the same.
-        Whitespace in most cases is ignored, and attribute ordering is not
-        significant. The passed-in arguments must be valid XML.
+        Assert that two XML snippets are semantically the same.
+        Whitespace in most cases is ignored and attribute ordering is not
+        significant. The arguments must be valid XML.
         """
         try:
             result = compare_xml(xml1, xml2)
@@ -754,9 +756,9 @@ class SimpleTestCase(unittest.TestCase):
 
     def assertXMLNotEqual(self, xml1, xml2, msg=None):
         """
-        Asserts that two XML snippets are not semantically equivalent.
-        Whitespace in most cases is ignored, and attribute ordering is not
-        significant. The passed-in arguments must be valid XML.
+        Assert that two XML snippets are not semantically equivalent.
+        Whitespace in most cases is ignored and attribute ordering is not
+        significant. The arguments must be valid XML.
         """
         try:
             result = compare_xml(xml1, xml2)
@@ -795,12 +797,12 @@ class TransactionTestCase(SimpleTestCase):
     allow_database_queries = True
 
     def _pre_setup(self):
-        """Performs any pre-test setup. This includes:
-
-        * If the class has an 'available_apps' attribute, restricting the app
-          registry to these applications, then firing post_migrate -- it must
-          run with the correct set of applications for the test case.
-        * If the class has a 'fixtures' attribute, installing these fixtures.
+        """
+        Perform pre-test setup:
+        * If the class has an 'available_apps' attribute, restrict the app
+          registry to these applications, then fire the post_migrate signal --
+          it must run with the correct set of applications for the test case.
+        * If the class has a 'fixtures' attribute, install those fixtures.
         """
         super()._pre_setup()
         if self.available_apps is not None:
@@ -876,11 +878,11 @@ class TransactionTestCase(SimpleTestCase):
         return True
 
     def _post_teardown(self):
-        """Performs any post-test things. This includes:
-
-        * Flushing the contents of the database, to leave a clean slate. If
-          the class has an 'available_apps' attribute, post_migrate isn't fired.
-        * Force-closing the connection, so the next test gets a clean cursor.
+        """
+        Perform post-test things:
+        * Flush the contents of the database to leave a clean slate. If the
+          class has an 'available_apps' attribute, don't fire post_migrate.
+        * Force-close the connection so the next test gets a clean cursor.
         """
         try:
             self._fixture_teardown()
@@ -944,16 +946,13 @@ class TransactionTestCase(SimpleTestCase):
 
 
 def connections_support_transactions():
-    """
-    Returns True if all connections support transactions.
-    """
-    return all(conn.features.supports_transactions
-               for conn in connections.all())
+    """Return True if all connections support transactions."""
+    return all(conn.features.supports_transactions for conn in connections.all())
 
 
 class TestCase(TransactionTestCase):
     """
-    Similar to TransactionTestCase, but uses `transaction.atomic()` to achieve
+    Similar to TransactionTestCase, but use `transaction.atomic()` to achieve
     test isolation.
 
     In most situations, TestCase should be preferred to TransactionTestCase as
@@ -966,7 +965,7 @@ class TestCase(TransactionTestCase):
     """
     @classmethod
     def _enter_atomics(cls):
-        """Helper method to open atomic blocks for multiple databases"""
+        """Open atomic blocks for multiple databases."""
         atomics = {}
         for db_name in cls._databases_names():
             atomics[db_name] = transaction.atomic(using=db_name)
@@ -975,7 +974,7 @@ class TestCase(TransactionTestCase):
 
     @classmethod
     def _rollback_atomics(cls, atomics):
-        """Rollback atomic blocks opened through the previous method"""
+        """Rollback atomic blocks opened by the previous method."""
         for db_name in reversed(cls._databases_names()):
             transaction.set_rollback(True, using=db_name)
             atomics[db_name].__exit__(None, None, None)
@@ -1014,7 +1013,7 @@ class TestCase(TransactionTestCase):
 
     @classmethod
     def setUpTestData(cls):
-        """Load initial data for the TestCase"""
+        """Load initial data for the TestCase."""
         pass
 
     def _should_reload_connections(self):
@@ -1050,7 +1049,7 @@ class TestCase(TransactionTestCase):
 
 
 class CheckCondition:
-    """Descriptor class for deferred condition checking"""
+    """Descriptor class for deferred condition checking."""
     def __init__(self, *conditions):
         self.conditions = conditions
 
@@ -1095,9 +1094,7 @@ def _deferredSkip(condition, reason):
 
 
 def skipIfDBFeature(*features):
-    """
-    Skip a test if a database has at least one of the named features.
-    """
+    """Skip a test if a database has at least one of the named features."""
     return _deferredSkip(
         lambda: any(getattr(connection.features, feature, False) for feature in features),
         "Database has feature(s) %s" % ", ".join(features)
@@ -1105,9 +1102,7 @@ def skipIfDBFeature(*features):
 
 
 def skipUnlessDBFeature(*features):
-    """
-    Skip a test unless a database has all the named features.
-    """
+    """Skip a test unless a database has all the named features."""
     return _deferredSkip(
         lambda: not all(getattr(connection.features, feature, False) for feature in features),
         "Database doesn't support feature(s): %s" % ", ".join(features)
@@ -1115,9 +1110,7 @@ def skipUnlessDBFeature(*features):
 
 
 def skipUnlessAnyDBFeature(*features):
-    """
-    Skip a test unless a database has any of the named features.
-    """
+    """Skip a test unless a database has any of the named features."""
     return _deferredSkip(
         lambda: not any(getattr(connection.features, feature, False) for feature in features),
         "Database doesn't support any of the feature(s): %s" % ", ".join(features)
@@ -1126,11 +1119,9 @@ def skipUnlessAnyDBFeature(*features):
 
 class QuietWSGIRequestHandler(WSGIRequestHandler):
     """
-    Just a regular WSGIRequestHandler except it doesn't log to the standard
-    output any of the requests received, so as to not clutter the output for
-    the tests' results.
+    A WSGIRequestHandler that doesn't log to standard output any of the
+    requests received, so as to not clutter the test result output.
     """
-
     def log_message(*args):
         pass
 
@@ -1147,17 +1138,14 @@ class FSFilesHandler(WSGIHandler):
 
     def _should_handle(self, path):
         """
-        Checks if the path should be handled. Ignores the path if:
-
+        Check if the path should be handled. Ignore the path if:
         * the host is provided as part of the base_url
         * the request's path isn't under the media path (or equal)
         """
         return path.startswith(self.base_url[2]) and not self.base_url[1]
 
     def file_path(self, url):
-        """
-        Returns the relative path to the file on disk for the given URL.
-        """
+        """Return the relative path to the file on disk for the given URL."""
         relative_url = url[len(self.base_url[2]):]
         return url2pathname(relative_url)
 
@@ -1191,7 +1179,6 @@ class _StaticFilesHandler(FSFilesHandler):
     Handler for serving static files. A private class that is meant to be used
     solely as a convenience by LiveServerThread.
     """
-
     def get_base_dir(self):
         return settings.STATIC_ROOT
 
@@ -1204,7 +1191,6 @@ class _MediaFilesHandler(FSFilesHandler):
     Handler for serving the media files. A private class that is meant to be
     used solely as a convenience by LiveServerThread.
     """
-
     def get_base_dir(self):
         return settings.MEDIA_ROOT
 
@@ -1213,9 +1199,7 @@ class _MediaFilesHandler(FSFilesHandler):
 
 
 class LiveServerThread(threading.Thread):
-    """
-    Thread for running a live http server while the tests are running.
-    """
+    """Thread for running a live http server while the tests are running."""
 
     def __init__(self, host, static_handler, connections_override=None):
         self.host = host
@@ -1228,8 +1212,8 @@ class LiveServerThread(threading.Thread):
 
     def run(self):
         """
-        Sets up the live server and databases, and then loops over handling
-        http requests.
+        Set up the live server and databases, and then loop over handling
+        HTTP requests.
         """
         if self.connections_override:
             # Override this thread's database connections with the ones
@@ -1263,14 +1247,14 @@ class LiveServerThread(threading.Thread):
 
 class LiveServerTestCase(TransactionTestCase):
     """
-    Does basically the same as TransactionTestCase but also launches a live
-    http server in a separate thread so that the tests may use another testing
+    Do basically the same as TransactionTestCase but also launch a live HTTP
+    server in a separate thread so that the tests may use another testing
     framework, such as Selenium for example, instead of the built-in dummy
     client.
-    Note that it inherits from TransactionTestCase instead of TestCase because
-    the threads do not share the same transactions (unless if using in-memory
-    sqlite) and each thread needs to commit all their transactions so that the
-    other thread can see the changes.
+    It inherits from TransactionTestCase instead of TestCase because the
+    threads don't share the same transactions (unless if using in-memory sqlite)
+    and each thread needs to commit all their transactions so that the other
+    thread can see the changes.
     """
     host = 'localhost'
     server_thread_class = LiveServerThread
@@ -1338,14 +1322,13 @@ class LiveServerTestCase(TransactionTestCase):
 
 class SerializeMixin:
     """
-    Mixin to enforce serialization of TestCases that share a common resource.
+    Enforce serialization of TestCases that share a common resource.
 
     Define a common 'lockfile' for each set of TestCases to serialize. This
     file must exist on the filesystem.
 
-    Place it early in the MRO in order to isolate setUpClass / tearDownClass.
+    Place it early in the MRO in order to isolate setUpClass()/tearDownClass().
     """
-
     lockfile = None
 
     @classmethod
diff --git a/django/test/utils.py b/django/test/utils.py
index 88158e89d6..efd1b49c88 100644
--- a/django/test/utils.py
+++ b/django/test/utils.py
@@ -55,7 +55,8 @@ class Approximate:
 
 
 class ContextList(list):
-    """A wrapper that provides direct key access to context items contained
+    """
+    A wrapper that provides direct key access to context items contained
     in a list of context objects.
     """
     def __getitem__(self, key):
@@ -93,8 +94,8 @@ class ContextList(list):
 
 def instrumented_test_render(self, context):
     """
-    An instrumented Template render method, providing a signal
-    that can be intercepted by the test system Client
+    An instrumented Template render method, providing a signal that can be
+    intercepted by the test Client.
     """
     template_rendered.send(sender=self, template=self, context=context)
     return self.nodelist.render(context)
@@ -157,9 +158,7 @@ def teardown_test_environment():
 
 
 def setup_databases(verbosity, interactive, keepdb=False, debug_sql=False, parallel=0, **kwargs):
-    """
-    Create the test databases.
-    """
+    """Create the test databases."""
     test_databases, mirrored_aliases = get_unique_databases_and_mirrors()
 
     old_names = []
@@ -290,9 +289,7 @@ def get_unique_databases_and_mirrors():
 
 
 def teardown_databases(old_config, verbosity, parallel=0, keepdb=False):
-    """
-    Destroy all the non-mirror databases.
-    """
+    """Destroy all the non-mirror databases."""
     for connection, old_name, destroy in old_config:
         if destroy:
             if parallel > 1:
@@ -387,10 +384,10 @@ class TestContextDecorator:
 
 class override_settings(TestContextDecorator):
     """
-    Acts as either a decorator or a context manager. If it's a decorator it
-    takes a function and returns a wrapped function. If it's a contextmanager
-    it's used with the ``with`` statement. In either event entering/exiting
-    are called before and after, respectively, the function/block is executed.
+    Act as either a decorator or a context manager. If it's a decorator, take a
+    function and return a wrapped function. If it's a contextmanager, use it
+    with the ``with`` statement. In either event, entering/exiting are called
+    before and after, respectively, the function/block is executed.
     """
     def __init__(self, **kwargs):
         self.options = kwargs
@@ -444,7 +441,7 @@ class override_settings(TestContextDecorator):
 
 class modify_settings(override_settings):
     """
-    Like override_settings, but makes it possible to append, prepend or remove
+    Like override_settings, but makes it possible to append, prepend, or remove
     items instead of redefining the entire list.
     """
     def __init__(self, *args, **kwargs):
@@ -492,7 +489,7 @@ class modify_settings(override_settings):
 
 class override_system_checks(TestContextDecorator):
     """
-    Acts as a decorator. Overrides list of registered system checks.
+    Act as a decorator. Override list of registered system checks.
     Useful when you override `INSTALLED_APPS`, e.g. if you exclude `auth` app,
     you also need to exclude its system checks.
     """
@@ -516,10 +513,10 @@ class override_system_checks(TestContextDecorator):
 
 
 def compare_xml(want, got):
-    """Tries to do a 'xml-comparison' of want and got.  Plain string
-    comparison doesn't always work because, for example, attribute
-    ordering should not be important. Comment nodes are not considered in the
-    comparison. Leading and trailing whitespace is ignored on both chunks.
+    """
+    Try to do a 'xml-comparison' of want and got. Plain string comparison
+    doesn't always work because, for example, attribute ordering should not be
+    important. Ignore comment nodes and leading and trailing whitespace.
 
     Based on https://github.com/lxml/lxml/blob/master/src/lxml/doctestcompare.py
     """
@@ -794,9 +791,7 @@ def require_jinja2(test_func):
 
 
 class override_script_prefix(TestContextDecorator):
-    """
-    Decorator or context manager to temporary override the script prefix.
-    """
+    """Decorator or context manager to temporary override the script prefix."""
     def __init__(self, prefix):
         self.prefix = prefix
         super().__init__()
@@ -840,7 +835,6 @@ class isolate_apps(TestContextDecorator):
     `kwarg_name`: keyword argument passing the isolated registry if used as a
                   function decorator.
     """
-
     def __init__(self, *installed_apps, **kwargs):
         self.installed_apps = installed_apps
         super().__init__(**kwargs)
@@ -856,9 +850,7 @@ class isolate_apps(TestContextDecorator):
 
 
 def tag(*tags):
-    """
-    Decorator to add tags to a test class or method.
-    """
+    """Decorator to add tags to a test class or method."""
     def decorator(obj):
         setattr(obj, 'tags', set(tags))
         return obj