http.parse_date returns timzeone-aware valueparse_date-timezone

14 files changed, 236 insertions, 188 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 35aa037c..ce39938e 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -19,6 +19,15 @@ Unreleased
 -   Deprecate the ``environ["werkzeug.server.shutdown"]`` function
     that is available when running the development server. :issue:`1752`
 -   Remove the unused, internal ``posixemulation`` module. :issue:`1759`
+-   All ``datetime`` values are timezone-aware with
+    ``tzinfo=timezone.utc``. This applies to anything using
+    ``http.parse_date``: ``Request.date``, ``.if_modified_since``,
+    ``.if_unmodified_since``; ``Response.date``, ``.expires``,
+    ``.last_modified``, ``.retry_after``; ``parse_if_range_header``, and
+    ``IfRange.date``. When comparing values, the other values must also
+    be aware, or these values must be made naive. When passing
+    parameters or setting attributes, naive values are still assumed to
+    be in UTC. :pr:`2040`
 -   Merge all request and response wrapper mixin code into single
     ``Request`` and ``Response`` classes. Using the mixin classes is no
     longer necessary and will show a deprecation warning. Checking
@@ -86,6 +95,11 @@ Unreleased
     :pr:`1915`
 -   Add arguments to ``delete_cookie`` to match ``set_cookie`` and the
     attributes modern browsers expect. :pr:`1889`
+-   ``utils.cookie_date`` is deprecated, use ``utils.http_date``
+    instead. The value for ``Set-Cookie expires`` is no longer "-"
+    delimited. :pr:`2040`
+-   ``utils.http_date``, and attributes and values that use it, no
+    longer accept ``time.struct_time`` tuples. :pr:`2040`
 -   Use ``request.headers`` instead of ``request.environ`` to look up
     header attributes. :pr:`1808`
 -   The test ``Client`` request methods (``client.get``, etc.) always
diff --git a/docs/http.rst b/docs/http.rst
index 0f16cc8f..3db53506 100644
--- a/docs/http.rst
+++ b/docs/http.rst
@@ -9,21 +9,32 @@ that are useful when implementing WSGI middlewares or whenever you are
 operating on a lower level layer.  All this functionality is also exposed
 from request and response objects.
 
-Date Functions
-==============
 
-The following functions simplify working with times in an HTTP context.
-Werkzeug uses offset-naive :class:`~datetime.datetime` objects internally
-that store the time in UTC.  If you're working with timezones in your
-application make sure to replace the tzinfo attribute with a UTC timezone
-information before processing the values.
+Datetime Functions
+==================
 
-.. autofunction:: cookie_date
+These functions simplify working with times in an HTTP context. Werkzeug
+produces timezone-aware :class:`~datetime.datetime` objects in UTC. When
+passing datetime objects to Werkzeug, it assumes any naive datetime is
+in UTC.
 
-.. autofunction:: http_date
+When comparing datetime values from Werkzeug, your own datetime objects
+must also be timezone-aware, or you must make the values from Werkzeug
+naive.
+
+*   ``dt = datetime.now(timezone.utc)`` gets the current time in UTC.
+*   ``dt = datetime(..., tzinfo=timezone.utc)`` creates a time in UTC.
+*   ``dt = dt.replace(tzinfo=timezone.utc)`` makes a naive object aware
+    by assuming it's in UTC.
+*   ``dt = dt.replace(tzinfo=None)`` makes an aware object naive.
 
 .. autofunction:: parse_date
 
+.. autofunction:: http_date
+
+.. autofunction:: cookie_date
+
+
 Header Parsing
 ==============
 
diff --git a/docs/quickstart.rst b/docs/quickstart.rst
index abe5c798..be4574f2 100644
--- a/docs/quickstart.rst
+++ b/docs/quickstart.rst
@@ -185,7 +185,7 @@ True
 E-tags and other conditional headers are available in parsed form as well:
 
 >>> request.if_modified_since
-datetime.datetime(2009, 2, 20, 10, 10, 25)
+datetime.datetime(2009, 2, 20, 10, 10, 25, tzinfo=datetime.timezone.utc)
 >>> request.if_none_match
 <ETags '"e51c9-1e5d-46356dc86c640"'>
 >>> request.cache_control
@@ -253,8 +253,8 @@ retrieve them:
 
 >>> response.content_length
 12
->>> from datetime import datetime
->>> response.date = datetime(2009, 2, 20, 17, 42, 51)
+>>> from datetime import datetime, timezone
+>>> response.date = datetime(2009, 2, 20, 17, 42, 51, tzinfo=timezone.utc)
 >>> response.headers['Date']
 'Fri, 20 Feb 2009 17:42:51 GMT'
 
diff --git a/src/werkzeug/_internal.py b/src/werkzeug/_internal.py
index afb7f3f3..8a0c17b6 100644
--- a/src/werkzeug/_internal.py
+++ b/src/werkzeug/_internal.py
@@ -8,8 +8,8 @@ import typing
 import typing as t
 from datetime import date
 from datetime import datetime
+from datetime import timezone
 from itertools import chain
-from time import struct_time
 from weakref import WeakKeyDictionary
 
 if t.TYPE_CHECKING:
@@ -295,20 +295,26 @@ def _parse_signature(func):
     return parse
 
 
-def _date_to_unix(arg: t.Union[datetime, int, float, struct_time]) -> int:
-    """Converts a timetuple, integer or datetime object into the seconds from
-    epoch in utc.
-    """
-    if isinstance(arg, datetime):
-        arg = arg.utctimetuple()
-    elif isinstance(arg, (int, float)):
-        return int(arg)
-    year, month, day, hour, minute, second = arg[:6]
-    days = date(year, month, 1).toordinal() - _epoch_ord + day - 1
-    hours = days * 24 + hour
-    minutes = hours * 60 + minute
-    seconds = minutes * 60 + second
-    return seconds
+@typing.overload
+def _dt_as_utc(dt: None) -> None:
+    ...
+
+
+@typing.overload
+def _dt_as_utc(dt: datetime) -> datetime:
+    ...
+
+
+def _dt_as_utc(dt):
+    if dt is None:
+        return dt
+
+    if dt.tzinfo is None:
+        return dt.replace(tzinfo=timezone.utc)
+    elif dt.tzinfo != timezone.utc:
+        return dt.astimezone(timezone.utc)
+
+    return dt
 
 
 _TAccessorValue = t.TypeVar("_TAccessorValue")
diff --git a/src/werkzeug/http.py b/src/werkzeug/http.py
index 4b7a0489..9e6e8273 100644
--- a/src/werkzeug/http.py
+++ b/src/werkzeug/http.py
@@ -1,15 +1,14 @@
 import base64
+import email.utils
 import re
 import typing
 import typing as t
 import warnings
 from datetime import datetime
 from datetime import timedelta
-from email.utils import parsedate_tz
+from datetime import timezone
 from enum import Enum
 from hashlib import sha1
-from time import gmtime
-from time import struct_time
 from time import time
 from urllib.parse import unquote_to_bytes as _unquote
 from urllib.request import parse_http_list as _parse_list_header
@@ -20,6 +19,7 @@ from ._internal import _make_cookie_domain
 from ._internal import _to_bytes
 from ._internal import _to_str
 from ._internal import _wsgi_decoding_dance
+from werkzeug._internal import _dt_as_utc
 
 if t.TYPE_CHECKING:
     from wsgiref.types import WSGIEnvironment
@@ -699,6 +699,9 @@ def parse_if_range_header(value: t.Optional[str]) -> "ds.IfRange":
     """Parses an if-range header which can be an etag or a date.  Returns
     a :class:`~werkzeug.datastructures.IfRange` object.
 
+    .. versionchanged:: 2.0.0
+        If the value represents a datetime, it is timezone-aware.
+
     .. versionadded:: 0.7
     """
     if not value:
@@ -892,97 +895,69 @@ def generate_etag(data: bytes) -> str:
 
 
 def parse_date(value: t.Optional[str]) -> t.Optional[datetime]:
-    """Parse one of the following date formats into a datetime object:
-
-    .. sourcecode:: text
+    """Parse an :rfc:`2822` date into a timezone-aware
+    :class:`datetime.datetime` object, or ``None`` if parsing fails.
 
-        Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
-        Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
-        Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
+    This is a wrapper for :func:`email.utils.parsedate_to_datetime`. It
+    returns ``None`` if parsing fails instead of raising an exception,
+    and always returns a timezone-aware datetime object. If the string
+    doesn't have timezone information, it is assumed to be UTC.
 
-    If parsing fails the return value is `None`.
+    :param value: A string with a supported date format.
 
-    :param value: a string with a supported date format.
-    :return: a :class:`datetime.datetime` object.
+    .. versionchanged:: 2.0.0
+        Return a timezone-aware datetime object. Use
+        ``email.utils.parsedate_to_datetime``.
     """
-    if value:
-        t = parsedate_tz(value.strip())
-        if t is not None:
-            try:
-                year = t[0]
-                # unfortunately that function does not tell us if two digit
-                # years were part of the string, or if they were prefixed
-                # with two zeroes.  So what we do is to assume that 69-99
-                # refer to 1900, and everything below to 2000
-                if 0 <= year <= 68:
-                    year += 2000
-                elif 69 <= year <= 99:
-                    year += 1900
-                return datetime(*((year,) + t[1:7])) - timedelta(seconds=t[-1] or 0)
-            except (ValueError, OverflowError):
-                return None
-    return None
-
+    if value is None:
+        return None
 
-_t_date_input = t.Optional[t.Union[datetime, int, float, struct_time]]
-
-
-def _dump_date(d: _t_date_input, delim: str) -> str:
-    """Used for `http_date` and `cookie_date`."""
-    if d is None:
-        d = gmtime()
-    elif isinstance(d, datetime):
-        d = d.utctimetuple()
-    elif isinstance(d, (int, float)):
-        d = gmtime(d)
-    weekday = ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")[d.tm_wday]
-    month = (
-        "Jan",
-        "Feb",
-        "Mar",
-        "Apr",
-        "May",
-        "Jun",
-        "Jul",
-        "Aug",
-        "Sep",
-        "Oct",
-        "Nov",
-        "Dec",
-    )[d.tm_mon - 1]
-    return (
-        f"{weekday}, {d.tm_mday:02d}{delim}{month}{delim}{d.tm_year:04d}"
-        f" {d.tm_hour:02d}:{d.tm_min:02d}:{d.tm_sec:02d} GMT"
-    )
+    try:
+        dt = email.utils.parsedate_to_datetime(value)
+    except TypeError:
+        return None
 
+    if dt.tzinfo is None:
+        return dt.replace(tzinfo=timezone.utc)
 
-def cookie_date(expires: _t_date_input = None) -> str:
-    """Formats the time to ensure compatibility with Netscape's cookie
-    standard.
+    return dt
 
-    Accepts a floating point number expressed in seconds since the epoch in, a
-    datetime object or a timetuple.  All times in UTC.  The :func:`parse_date`
-    function can be used to parse such a date.
 
-    Outputs a string in the format ``Wdy, DD-Mon-YYYY HH:MM:SS GMT``.
+def cookie_date(expires: t.Optional[t.Union[datetime, int, float]] = None) -> str:
+    """Format a datetime object or timestamp into an :rfc:`2822` date
+    string for ``Set-Cookie expires``.
 
-    :param expires: If provided that date is used, otherwise the current.
+    .. deprecated:: 2.0.0
+        Use :func:`http_date` instead. Will be removed in version 2.1.
     """
-    return _dump_date(expires, "-")
+    warnings.warn(
+        "'cookie_date' is deprecated and will be removed in Werkzeug"
+        " version 2.1. Use 'http_date' instead.",
+        DeprecationWarning,
+        stacklevel=2,
+    )
+    return http_date(expires)
 
 
-def http_date(timestamp: _t_date_input = None) -> str:
-    """Formats the time to match the RFC1123 date format.
+def http_date(timestamp: t.Optional[t.Union[datetime, int, float]] = None) -> str:
+    """Format a datetime object or timestamp into an :rfc:`2822` date
+    string.
 
-    Accepts a floating point number expressed in seconds since the epoch in, a
-    datetime object or a timetuple.  All times in UTC.  The :func:`parse_date`
-    function can be used to parse such a date.
+    This is a wrapper for :func:`email.utils.format_datetime` and
+    ``.formatdate``. It assumes naive datetime objects are in UTC
+    instead of raising an exception.
 
-    Outputs a string in the format ``Wdy, DD Mon YYYY HH:MM:SS GMT``.
+    :param timestamp: The datetime or timestamp to format. Defaults to
+        the current time.
 
-    :param timestamp: If provided that date is used, otherwise the current.
+    .. versionchanged:: 2.0.0
+        Use ``email.utils.format_datetime``.
     """
-    return _dump_date(timestamp, " ")
+    if isinstance(timestamp, datetime):
+        timestamp = _dt_as_utc(timestamp)
+        return email.utils.format_datetime(timestamp, usegmt=True)
+
+    return email.utils.formatdate(timestamp, usegmt=True)
 
 
 def parse_age(value: t.Optional[str] = None) -> t.Optional[timedelta]:
@@ -1061,10 +1036,10 @@ def is_resource_modified(
     if isinstance(last_modified, str):
         last_modified = parse_date(last_modified)
 
-    # ensure that microsecond is zero because the HTTP spec does not transmit
-    # that either and we might have some false positives.  See issue #39
+    # HTTP doesn't use microsecond, remove it to avoid false positive
+    # comparisons. Mark naive datetimes as UTC.
     if last_modified is not None:
-        last_modified = last_modified.replace(microsecond=0)
+        last_modified = _dt_as_utc(last_modified.replace(microsecond=0))
 
     if_range = None
     if not ignore_if_range and "HTTP_RANGE" in environ:
@@ -1285,9 +1260,9 @@ def dump_cookie(
         max_age = (max_age.days * 60 * 60 * 24) + max_age.seconds
     if expires is not None:
         if not isinstance(expires, str):
-            expires = cookie_date(expires)
+            expires = http_date(expires)
     elif max_age is not None and sync_expires:
-        expires = cookie_date(time() + max_age)
+        expires = http_date(time() + max_age)
 
     if samesite is not None:
         samesite = samesite.title()
diff --git a/src/werkzeug/middleware/shared_data.py b/src/werkzeug/middleware/shared_data.py
index 776498ee..2578f7ae 100644
--- a/src/werkzeug/middleware/shared_data.py
+++ b/src/werkzeug/middleware/shared_data.py
@@ -14,8 +14,8 @@ import pkgutil
 import posixpath
 import typing as t
 from datetime import datetime
+from datetime import timezone
 from io import BytesIO
-from time import mktime
 from time import time
 from zlib import adler32
 
@@ -148,7 +148,7 @@ class SharedDataMiddleware:
     def _opener(self, filename: str) -> _TOpener:
         return lambda: (
             open(filename, "rb"),
-            datetime.utcfromtimestamp(os.path.getmtime(filename)),
+            datetime.fromtimestamp(os.path.getmtime(filename), tz=timezone.utc),
             int(os.path.getsize(filename)),
         )
 
@@ -156,7 +156,7 @@ class SharedDataMiddleware:
         return lambda x: (os.path.basename(filename), self._opener(filename))
 
     def get_package_loader(self, package: str, package_path: str) -> _TLoader:
-        load_time = datetime.utcnow()
+        load_time = datetime.now(timezone.utc)
         provider = pkgutil.get_loader(package)
 
         if hasattr(provider, "get_resource_reader"):
@@ -185,7 +185,9 @@ class SharedDataMiddleware:
                     basename,
                     lambda: (
                         resource,
-                        datetime.utcfromtimestamp(os.path.getmtime(resource.name)),
+                        datetime.fromtimestamp(
+                            os.path.getmtime(resource.name), tz=timezone.utc
+                        ),
                         os.path.getsize(resource.name),
                     ),
                 )
@@ -238,7 +240,7 @@ class SharedDataMiddleware:
                 get_filesystem_encoding()
             )
 
-        timestamp = mktime(mtime.timetuple())
+        timestamp = mtime.timestamp()
         checksum = adler32(real_filename) & 0xFFFFFFFF  # type: ignore
         return f"wzsdm-{timestamp}-{file_size}-{checksum}"
 
diff --git a/src/werkzeug/sansio/request.py b/src/werkzeug/sansio/request.py
index 3aec37c1..de0b7edc 100644
--- a/src/werkzeug/sansio/request.py
+++ b/src/werkzeug/sansio/request.py
@@ -229,7 +229,11 @@ class Request:
         parse_date,
         doc="""The Date general-header field represents the date and
         time at which the message was originated, having the same
-        semantics as orig-date in RFC 822.""",
+        semantics as orig-date in RFC 822.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """,
         read_only=True,
     )
     max_forwards = header_property(
@@ -341,21 +345,30 @@ class Request:
 
     @cached_property
     def if_modified_since(self) -> t.Optional[datetime]:
-        """The parsed `If-Modified-Since` header as datetime object."""
+        """The parsed `If-Modified-Since` header as a datetime object.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """
         return parse_date(self.headers.get("If-Modified-Since"))
 
     @cached_property
     def if_unmodified_since(self) -> t.Optional[datetime]:
-        """The parsed `If-Unmodified-Since` header as datetime object."""
+        """The parsed `If-Unmodified-Since` header as a datetime object.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """
         return parse_date(self.headers.get("If-Unmodified-Since"))
 
     @cached_property
     def if_range(self) -> IfRange:
-        """The parsed `If-Range` header.
+        """The parsed ``If-Range`` header.
 
-        .. versionadded:: 0.7
+        .. versionchanged:: 2.0.0
+            ``IfRange.date`` is timezone-aware.
 
-        :rtype: :class:`~werkzeug.datastructures.IfRange`
+        .. versionadded:: 0.7
         """
         return parse_if_range_header(self.headers.get("If-Range"))
 
diff --git a/src/werkzeug/sansio/response.py b/src/werkzeug/sansio/response.py
index b7b5a4a1..f0c5586e 100644
--- a/src/werkzeug/sansio/response.py
+++ b/src/werkzeug/sansio/response.py
@@ -2,6 +2,7 @@ import typing
 import typing as t
 from datetime import datetime
 from datetime import timedelta
+from datetime import timezone
 
 from .._internal import _to_str
 from ..datastructures import Headers
@@ -382,7 +383,11 @@ class Response:
         http_date,
         doc="""The Date general-header field represents the date and
         time at which the message was originated, having the same
-        semantics as orig-date in RFC 822.""",
+        semantics as orig-date in RFC 822.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """,
     )
     expires = header_property(
         "Expires",
@@ -391,7 +396,11 @@ class Response:
         http_date,
         doc="""The Expires entity-header field gives the date/time after
         which the response is considered stale. A stale cache entry may
-        not normally be returned by a cache.""",
+        not normally be returned by a cache.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """,
     )
     last_modified = header_property(
         "Last-Modified",
@@ -400,7 +409,11 @@ class Response:
         http_date,
         doc="""The Last-Modified entity-header field indicates the date
         and time at which the origin server believes the variant was
-        last modified.""",
+        last modified.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
+        """,
     )
 
     @property
@@ -410,12 +423,15 @@ class Response:
         service is expected to be unavailable to the requesting client.
 
         Time in seconds until expiration or date.
+
+        .. versionchanged:: 2.0.0
+            The datetime object is timezone-aware.
         """
         value = self.headers.get("retry-after")
         if value is None:
             return None
         elif value.isdigit():
-            return datetime.utcnow() + timedelta(seconds=int(value))
+            return datetime.now(timezone.utc) + timedelta(seconds=int(value))
         return parse_date(value)
 
     @retry_after.setter
diff --git a/src/werkzeug/serving.py b/src/werkzeug/serving.py
index dd6922a6..a5526d03 100644
--- a/src/werkzeug/serving.py
+++ b/src/werkzeug/serving.py
@@ -22,6 +22,7 @@ import typing as t
 import warnings
 from datetime import datetime as dt
 from datetime import timedelta
+from datetime import timezone
 from http.server import BaseHTTPRequestHandler
 from http.server import HTTPServer
 
@@ -475,8 +476,8 @@ def generate_adhoc_ssl_pair(
         .issuer_name(subject)
         .public_key(pkey.public_key())
         .serial_number(x509.random_serial_number())
-        .not_valid_before(dt.utcnow())
-        .not_valid_after(dt.utcnow() + timedelta(days=365))
+        .not_valid_before(dt.now(timezone.utc))
+        .not_valid_after(dt.now(timezone.utc) + timedelta(days=365))
         .add_extension(x509.ExtendedKeyUsage([x509.OID_SERVER_AUTH]), critical=False)
         .add_extension(x509.SubjectAlternativeName([x509.DNSName("*")]), critical=False)
         .sign(pkey, hashes.SHA256(), default_backend())
diff --git a/src/werkzeug/utils.py b/src/werkzeug/utils.py
index fafba99e..f834138d 100644
--- a/src/werkzeug/utils.py
+++ b/src/werkzeug/utils.py
@@ -11,7 +11,6 @@ import unicodedata
 import warnings
 from datetime import datetime
 from html.entities import name2codepoint
-from time import struct_time
 from time import time
 from zlib import adler32
 
@@ -564,7 +563,7 @@ def send_file(
     download_name: t.Optional[str] = None,
     conditional: bool = True,
     etag: t.Union[bool, str] = True,
-    last_modified: t.Optional[t.Union[datetime, int, float, struct_time]] = None,
+    last_modified: t.Optional[t.Union[datetime, int, float]] = None,
     max_age: t.Optional[
         t.Union[int, t.Callable[[t.Optional[t.Union[os.PathLike, str]]], int]]
     ] = None,
diff --git a/tests/test_http.py b/tests/test_http.py
index b0231192..dcb62ddb 100644
--- a/tests/test_http.py
+++ b/tests/test_http.py
@@ -1,5 +1,7 @@
 import base64
 from datetime import datetime
+from datetime import timedelta
+from datetime import timezone
 
 import pytest
 
@@ -239,27 +241,6 @@ class TestHTTPUtility:
         assert bool(etags)
         assert etags.contains_raw('W/"foo"')
 
-    def test_parse_date(self):
-        assert http.parse_date("Sun, 06 Nov 1994 08:49:37 GMT    ") == datetime(
-            1994, 11, 6, 8, 49, 37
-        )
-        assert http.parse_date("Sunday, 06-Nov-94 08:49:37 GMT") == datetime(
-            1994, 11, 6, 8, 49, 37
-        )
-        assert http.parse_date(" Sun Nov  6 08:49:37 1994") == datetime(
-            1994, 11, 6, 8, 49, 37
-        )
-        assert http.parse_date("foo") is None
-
-    def test_parse_date_overflows(self):
-        assert http.parse_date(" Sun 02 Feb 1343 08:49:37 GMT") == datetime(
-            1343, 2, 2, 8, 49, 37
-        )
-        assert http.parse_date("Thu, 01 Jan 1970 00:00:00 GMT") == datetime(
-            1970, 1, 1, 0, 0
-        )
-        assert http.parse_date("Thu, 33 Jan 1970 00:00:00 GMT") is None
-
     def test_remove_entity_headers(self):
         now = http.http_date()
         headers1 = [
@@ -430,12 +411,6 @@ class TestHTTPUtility:
             env, last_modified=datetime(2008, 1, 1, 13, 30), ignore_if_range=True
         )
 
-    def test_date_formatting(self):
-        assert http.cookie_date(0) == "Thu, 01-Jan-1970 00:00:00 GMT"
-        assert http.cookie_date(datetime(1970, 1, 1)) == "Thu, 01-Jan-1970 00:00:00 GMT"
-        assert http.http_date(0) == "Thu, 01 Jan 1970 00:00:00 GMT"
-        assert http.http_date(datetime(1970, 1, 1)) == "Thu, 01 Jan 1970 00:00:00 GMT"
-
     def test_parse_cookie(self):
         cookies = http.parse_cookie(
             "dismiss-top=6; CP=null*; PHPSESSID=0a539d42abc001cdc762809248d4beed;"
@@ -583,7 +558,7 @@ class TestRange:
 
         rv = http.parse_if_range_header("Thu, 01 Jan 1970 00:00:00 GMT")
         assert rv.etag is None
-        assert rv.date == datetime(1970, 1, 1)
+        assert rv.date == datetime(1970, 1, 1, tzinfo=timezone.utc)
         assert rv.to_header() == "Thu, 01 Jan 1970 00:00:00 GMT"
 
         for x in "", None:
@@ -660,18 +635,6 @@ class TestRange:
         assert rv.length == 100
         assert rv.units == "bytes"
 
-    @pytest.mark.parametrize(
-        ("args", "expected"),
-        (
-            ((1, 1, 1), "Mon, 01 Jan 0001 00:00:00 GMT"),
-            ((999, 1, 1), "Tue, 01 Jan 0999 00:00:00 GMT"),
-            ((1000, 1, 1), "Wed, 01 Jan 1000 00:00:00 GMT"),
-            ((2020, 1, 1), "Wed, 01 Jan 2020 00:00:00 GMT"),
-        ),
-    )
-    def test_http_date_lt_1000(self, args, expected):
-        assert http.http_date(datetime(*args)) == expected
-
 
 class TestRegression:
     def test_best_match_works(self):
@@ -699,3 +662,58 @@ def test_authorization_to_header(value: str) -> None:
     parsed = http.parse_authorization_header(value)
     assert parsed is not None
     assert parsed.to_header() == value
+
+
+@pytest.mark.parametrize(
+    ("value", "expect"),
+    [
+        (
+            "Sun, 06 Nov 1994 08:49:37 GMT    ",
+            datetime(1994, 11, 6, 8, 49, 37, tzinfo=timezone.utc),
+        ),
+        (
+            "Sunday, 06-Nov-94 08:49:37 GMT",
+            datetime(1994, 11, 6, 8, 49, 37, tzinfo=timezone.utc),
+        ),
+        (
+            " Sun Nov  6 08:49:37 1994",
+            datetime(1994, 11, 6, 8, 49, 37, tzinfo=timezone.utc),
+        ),
+        ("foo", None),
+        (
+            " Sun 02 Feb 1343 08:49:37 GMT",
+            datetime(1343, 2, 2, 8, 49, 37, tzinfo=timezone.utc),
+        ),
+        (
+            "Thu, 01 Jan 1970 00:00:00 GMT",
+            datetime(1970, 1, 1, tzinfo=timezone.utc),
+        ),
+        ("Thu, 33 Jan 1970 00:00:00 GMT", None),
+    ],
+)
+def test_parse_date(value, expect):
+    assert http.parse_date(value) == expect
+
+
+@pytest.mark.parametrize(
+    ("value", "expect"),
+    [
+        (
+            datetime(1994, 11, 6, 8, 49, 37, tzinfo=timezone.utc),
+            "Sun, 06 Nov 1994 08:49:37 GMT",
+        ),
+        (
+            datetime(1994, 11, 6, 8, 49, 37, tzinfo=timezone(timedelta(hours=-8))),
+            "Sun, 06 Nov 1994 16:49:37 GMT",
+        ),
+        (datetime(1994, 11, 6, 8, 49, 37), "Sun, 06 Nov 1994 08:49:37 GMT"),
+        (0, "Thu, 01 Jan 1970 00:00:00 GMT"),
+        (datetime(1970, 1, 1), "Thu, 01 Jan 1970 00:00:00 GMT"),
+        (datetime(1, 1, 1), "Mon, 01 Jan 0001 00:00:00 GMT"),
+        (datetime(999, 1, 1), "Tue, 01 Jan 0999 00:00:00 GMT"),
+        (datetime(1000, 1, 1), "Wed, 01 Jan 1000 00:00:00 GMT"),
+        (datetime(2020, 1, 1), "Wed, 01 Jan 2020 00:00:00 GMT"),
+    ],
+)
+def test_http_date(value, expect):
+    assert http.http_date(value) == expect
diff --git a/tests/test_internal.py b/tests/test_internal.py
index 6506beff..6e673fdc 100644
--- a/tests/test_internal.py
+++ b/tests/test_internal.py
@@ -1,4 +1,3 @@
-from datetime import datetime
 from warnings import filterwarnings
 from warnings import resetwarnings
 
@@ -10,14 +9,6 @@ from werkzeug.wrappers import Request
 from werkzeug.wrappers import Response
 
 
-def test_date_to_unix():
-    assert internal._date_to_unix(datetime(1970, 1, 1)) == 0
-    assert internal._date_to_unix(datetime(1970, 1, 1, 1, 0, 0)) == 3600
-    assert internal._date_to_unix(datetime(1970, 1, 1, 1, 1, 1)) == 3661
-    x = datetime(2010, 2, 15, 16, 15, 39)
-    assert internal._date_to_unix(x) == 1266250539
-
-
 def test_easteregg():
     req = Request.from_values("/?macgybarchakku")
     resp = Response.force_type(internal._easteregg(None), req)
diff --git a/tests/test_send_file.py b/tests/test_send_file.py
index 424fe602..159aeb5f 100644
--- a/tests/test_send_file.py
+++ b/tests/test_send_file.py
@@ -35,7 +35,7 @@ def test_x_sendfile():
 
 
 def test_last_modified():
-    last_modified = datetime.datetime(1999, 1, 1)
+    last_modified = datetime.datetime(1999, 1, 1, tzinfo=datetime.timezone.utc)
     rv = send_file(txt_path, environ, last_modified=last_modified)
     assert rv.last_modified == last_modified
     rv.close()
diff --git a/tests/test_wrappers.py b/tests/test_wrappers.py
index 13214302..dfb9a75c 100644
--- a/tests/test_wrappers.py
+++ b/tests/test_wrappers.py
@@ -3,6 +3,7 @@ import json
 import os
 from datetime import datetime
 from datetime import timedelta
+from datetime import timezone
 from io import BytesIO
 
 import pytest
@@ -258,7 +259,7 @@ def test_base_response():
         (
             "Set-Cookie",
             "foo=bar; Domain=example.org;"
-            " Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=60;"
+            " Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=60;"
             " Path=/blub; SameSite=Strict",
         ),
     ]
@@ -270,7 +271,7 @@ def test_base_response():
         ("Content-Type", "text/plain; charset=utf-8"),
         (
             "Set-Cookie",
-            "foo=; Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=0; Path=/",
+            "foo=; Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=0; Path=/",
         ),
     ]
 
@@ -434,8 +435,9 @@ def test_etag_request():
         assert etags.contains_weak("foo")
         assert not etags.contains("foo")
 
-    assert request.if_modified_since == datetime(2008, 1, 22, 11, 18, 44)
-    assert request.if_unmodified_since == datetime(2008, 1, 22, 11, 18, 44)
+    dt = datetime(2008, 1, 22, 11, 18, 44, tzinfo=timezone.utc)
+    assert request.if_modified_since == dt
+    assert request.if_unmodified_since == dt
 
 
 def test_user_agent():
@@ -910,7 +912,7 @@ def test_common_response_descriptors():
     del response.mimetype_params["charset"]
     assert response.content_type == "text/html; x-foo=yep"
 
-    now = datetime.utcnow().replace(microsecond=0)
+    now = datetime.now(timezone.utc).replace(microsecond=0)
 
     assert response.content_length is None
     response.content_length = "42"
@@ -967,7 +969,7 @@ def test_common_request_descriptors():
     assert request.mimetype_params == {"charset": "utf-8"}
     assert request.content_length == 23
     assert request.referrer == "http://www.example.com/"
-    assert request.date == datetime(2009, 2, 28, 19, 4, 35)
+    assert request.date == datetime(2009, 2, 28, 19, 4, 35, tzinfo=timezone.utc)
     assert request.max_forwards == 10
     assert "no-cache" in request.pragma
     assert request.content_encoding == "gzip"
@@ -1419,7 +1421,7 @@ class TestSetCookie:
             (
                 "Set-Cookie",
                 "foo=bar; Domain=example.org;"
-                " Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=60;"
+                " Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=60;"
                 " Secure; Path=/blub",
             ),
         ]
@@ -1442,7 +1444,7 @@ class TestSetCookie:
             (
                 "Set-Cookie",
                 "foo=bar; Domain=example.org;"
-                " Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=60;"
+                " Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=60;"
                 " HttpOnly; Path=/blub",
             ),
         ]
@@ -1465,7 +1467,7 @@ class TestSetCookie:
             (
                 "Set-Cookie",
                 "foo=bar; Domain=example.org;"
-                " Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=60;"
+                " Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=60;"
                 " Secure; HttpOnly; Path=/blub",
             ),
         ]
@@ -1487,7 +1489,7 @@ class TestSetCookie:
             (
                 "Set-Cookie",
                 "foo=bar; Domain=example.org;"
-                " Expires=Thu, 01-Jan-1970 00:00:00 GMT; Max-Age=60;"
+                " Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=60;"
                 " Path=/blub; SameSite=Strict",
             ),
         ]