Rely on external copy of iso8601external-iso8601

20 files changed, 29 insertions, 380 deletions

diff --git a/COPYING b/COPYING
index 452c080..fc6b993 100644
--- a/COPYING
+++ b/COPYING
@@ -29,8 +29,6 @@ Code that has been incorporated into Subunit from other projects will
 naturally be under its own license, and will retain that license.
 
 A known list of such code is maintained here:
-* The python/iso8601 module by Michael Twomey, distributed under an MIT style
-  licence - see python/iso8601/LICENSE for details.
 * The runtests.py and python/subunit/tests/TestUtil.py module are GPL test
   support modules. They are not installed by Subunit - they are only ever
   used on the build machine.  Copyright 2004 Canonical Limited.
diff --git a/Makefile.am b/Makefile.am
index 5d68c98..d677c49 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -12,11 +12,6 @@ EXTRA_DIST =  \
 	c/check-subunit-0.9.3.patch \
 	c/check-subunit-0.9.5.patch \
 	c/check-subunit-0.9.6.patch \
- 	python/iso8601/LICENSE \
- 	python/iso8601/README \
- 	python/iso8601/README.subunit \
- 	python/iso8601/setup.py \
- 	python/iso8601/test_iso8601.py \
  	python/subunit/tests/__init__.py \
  	python/subunit/tests/sample-script.py \
  	python/subunit/tests/sample-two-script.py \
@@ -73,7 +68,6 @@ pkgpython_PYTHON = \
 	python/subunit/chunked.py \
 	python/subunit/details.py \
 	python/subunit/filters.py \
-	python/subunit/iso8601.py \
 	python/subunit/progress_model.py \
 	python/subunit/run.py \
 	python/subunit/v2.py \
diff --git a/NEWS b/NEWS
index 8c6444e..8cdd791 100644
--- a/NEWS
+++ b/NEWS
@@ -5,12 +5,15 @@ subunit release notes
 NEXT (In development)
 ---------------------
 
-* Drop various compatibility wrappers for Python < 3.6.
+* Subunit now has a dependency on an external iso8601
+  module rather than shipping its own.
   (Jelmer Vernooij)
 
 IMPROVEMENTS
 ~~~~~~~~~~~~
 
+* Drop various compatibility wrappers for Python < 3.6.
+
 BUG FIXES
 ~~~~~~~~~
 
diff --git a/README.rst b/README.rst
index 86660aa..8b4c1a2 100644
--- a/README.rst
+++ b/README.rst
@@ -15,9 +15,6 @@
 
   See the COPYING file for full details on the licensing of Subunit.
 
-  subunit reuses iso8601 by Michael Twomey, distributed under an MIT style
-  licence - see python/iso8601/LICENSE for details.
-
 Subunit
 -------
 
diff --git a/python/iso8601/LICENSE b/python/iso8601/LICENSE
deleted file mode 100644
index 5ca93da..0000000
--- a/python/iso8601/LICENSE
+++ /dev/null
@@ -1,20 +0,0 @@
-Copyright (c) 2007 Michael Twomey
-
-Permission is hereby granted, free of charge, to any person obtaining a
-copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be included
-in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/python/iso8601/README b/python/iso8601/README
deleted file mode 100644
index 5ec9d45..0000000
--- a/python/iso8601/README
+++ /dev/null
@@ -1,26 +0,0 @@
-A simple package to deal with ISO 8601 date time formats.
-
-ISO 8601 defines a neutral, unambiguous date string format, which also
-has the property of sorting naturally.
-
-e.g. YYYY-MM-DDTHH:MM:SSZ or 2007-01-25T12:00:00Z
-
-Currently this covers only the most common date formats encountered, not
-all of ISO 8601 is handled.
-
-Currently the following formats are handled:
-
-* 2006-01-01T00:00:00Z
-* 2006-01-01T00:00:00[+-]00:00
-
-I'll add more as I encounter them in my day to day life. Patches with 
-new formats and tests will be gratefully accepted of course :)
-
-References:
-
-* http://www.cl.cam.ac.uk/~mgk25/iso-time.html - simple overview
-
-* http://hydracen.com/dx/iso8601.htm - more detailed enumeration of
-  valid formats.
-
-See the LICENSE file for the license this package is released under.
diff --git a/python/iso8601/README.subunit b/python/iso8601/README.subunit
deleted file mode 100644
index d1ed8a1..0000000
--- a/python/iso8601/README.subunit
+++ /dev/null
@@ -1,5 +0,0 @@
-This is a [slightly rearranged] import of http://pypi.python.org/pypi/iso8601/
-version 0.1.4. The OS X hidden files have been stripped, and the package
-turned into a single module, to simplify installation. The remainder of the
-source distribution is included in the subunit source tree at python/iso8601
-for reference.
diff --git a/python/iso8601/setup.py b/python/iso8601/setup.py
deleted file mode 100644
index cdb61ec..0000000
--- a/python/iso8601/setup.py
+++ /dev/null
@@ -1,58 +0,0 @@
-try:
-    from setuptools import setup
-except ImportError:
-    from distutils import setup
-
-long_description="""Simple module to parse ISO 8601 dates
-
-This module parses the most common forms of ISO 8601 date strings (e.g.
-2007-01-14T20:34:22+00:00) into datetime objects.
-
->>> import iso8601
->>> iso8601.parse_date("2007-01-25T12:00:00Z")
-datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.iso8601.Utc ...>)
->>>
-
-Changes
-=======
-
-0.1.4
------
-
-* The default_timezone argument wasn't being passed through correctly,
-  UTC was being used in every case. Fixes issue 10.
-
-0.1.3
------
-
-* Fixed the microsecond handling, the generated microsecond values were 
-  way too small. Fixes issue 9.
-
-0.1.2
------
-
-* Adding ParseError to __all__ in iso8601 module, allows people to import it.
-  Addresses issue 7.
-* Be a little more flexible when dealing with dates without leading zeroes.
-  This violates the spec a little, but handles more dates as seen in the 
-  field. Addresses issue 6.
-* Allow date/time separators other than T.
-
-0.1.1
------
-
-* When parsing dates without a timezone the specified default is used. If no
-  default is specified then UTC is used. Addresses issue 4.
-"""
-
-setup(
-    name="iso8601",
-    version="0.1.4",
-    description=long_description.split("\n")[0],
-    long_description=long_description,
-    author="Michael Twomey",
-    author_email="micktwomey+iso8601@gmail.com",
-    url="http://code.google.com/p/pyiso8601/",
-    packages=["iso8601"],
-    license="MIT",
-)
diff --git a/python/iso8601/test_iso8601.py b/python/iso8601/test_iso8601.py
deleted file mode 100644
index ae6741e..0000000
--- a/python/iso8601/test_iso8601.py
+++ /dev/null
@@ -1,112 +0,0 @@
-import iso8601
-
-
-def test_iso8601_regex():
-    assert iso8601.ISO8601_REGEX.match("2006-10-11T00:14:33Z")
-
-def test_timezone_regex():
-    assert iso8601.TIMEZONE_REGEX.match("+01:00")
-    assert iso8601.TIMEZONE_REGEX.match("+00:00")
-    assert iso8601.TIMEZONE_REGEX.match("+01:20")
-    assert iso8601.TIMEZONE_REGEX.match("-01:00")
-
-def test_parse_date():
-    d = iso8601.parse_date("2006-10-20T15:34:56Z")
-    assert d.year == 2006
-    assert d.month == 10
-    assert d.day == 20
-    assert d.hour == 15
-    assert d.minute == 34
-    assert d.second == 56
-    assert d.tzinfo == iso8601.UTC
-
-def test_parse_date_fraction():
-    d = iso8601.parse_date("2006-10-20T15:34:56.123Z")
-    assert d.year == 2006
-    assert d.month == 10
-    assert d.day == 20
-    assert d.hour == 15
-    assert d.minute == 34
-    assert d.second == 56
-    assert d.microsecond == 123000
-    assert d.tzinfo == iso8601.UTC
-
-def test_parse_date_fraction_2():
-    """From bug 6
-    
-    """
-    d = iso8601.parse_date("2007-5-7T11:43:55.328Z'")
-    assert d.year == 2007
-    assert d.month == 5
-    assert d.day == 7
-    assert d.hour == 11
-    assert d.minute == 43
-    assert d.second == 55
-    assert d.microsecond == 328000
-    assert d.tzinfo == iso8601.UTC
-
-def test_parse_date_tz():
-    d = iso8601.parse_date("2006-10-20T15:34:56.123+02:30")
-    assert d.year == 2006
-    assert d.month == 10
-    assert d.day == 20
-    assert d.hour == 15
-    assert d.minute == 34
-    assert d.second == 56
-    assert d.microsecond == 123000
-    assert d.tzinfo.tzname(None) == "+02:30"
-    offset = d.tzinfo.utcoffset(None)
-    assert offset.days == 0
-    assert offset.seconds == 60 * 60 * 2.5
-
-def test_parse_invalid_date():
-    try:
-        iso8601.parse_date(None)
-    except iso8601.ParseError:
-        pass
-    else:
-        assert 1 == 2
-
-def test_parse_invalid_date2():
-    try:
-        iso8601.parse_date("23")
-    except iso8601.ParseError:
-        pass
-    else:
-        assert 1 == 2
-
-def test_parse_no_timezone():
-    """issue 4 - Handle datetime string without timezone
-    
-    This tests what happens when you parse a date with no timezone. While not
-    strictly correct this is quite common. I'll assume UTC for the time zone
-    in this case.
-    """
-    d = iso8601.parse_date("2007-01-01T08:00:00")
-    assert d.year == 2007
-    assert d.month == 1
-    assert d.day == 1
-    assert d.hour == 8
-    assert d.minute == 0
-    assert d.second == 0
-    assert d.microsecond == 0
-    assert d.tzinfo == iso8601.UTC
-
-def test_parse_no_timezone_different_default():
-    tz = iso8601.FixedOffset(2, 0, "test offset")
-    d = iso8601.parse_date("2007-01-01T08:00:00", default_timezone=tz)
-    assert d.tzinfo == tz
-
-def test_space_separator():
-    """Handle a separator other than T
-    
-    """
-    d = iso8601.parse_date("2007-06-23 06:40:34.00Z")
-    assert d.year == 2007
-    assert d.month == 6
-    assert d.day == 23
-    assert d.hour == 6
-    assert d.minute == 40
-    assert d.second == 34
-    assert d.microsecond == 0
-    assert d.tzinfo == iso8601.UTC
diff --git a/python/subunit/__init__.py b/python/subunit/__init__.py
index 5e318c1..4203256 100644
--- a/python/subunit/__init__.py
+++ b/python/subunit/__init__.py
@@ -123,6 +123,7 @@ import unittest
 from io import BytesIO, StringIO
 from io import UnsupportedOperation as _UnsupportedOperation
 
+import iso8601
 from testtools import ExtendedToOriginalDecorator, content, content_type
 from testtools.compat import _b, _u
 from testtools.content import TracebackContent
@@ -135,7 +136,7 @@ except ImportError:
         "_StringException, check your version.")
 from testtools import CopyStreamResult, testresult
 
-from subunit import chunked, details, iso8601, test_results
+from subunit import chunked, details, test_results
 from subunit.v2 import ByteStreamToStreamResult, StreamResultToBytes
 
 # same format as sys.version_info: "A tuple containing the five components of
@@ -551,7 +552,7 @@ class TestProtocolServer(object):
     def _handleTime(self, offset, line):
         # Accept it, but do not do anything with it yet.
         try:
-            event_time = iso8601.parse_date(line[offset:-1])
+            event_time = iso8601.parse_date(line[offset:-1].decode())
         except TypeError:
             raise TypeError(_u("Failed to parse %r, got %r")
                 % (line, sys.exec_info[1]))
@@ -794,7 +795,7 @@ class TestProtocolClient(testresult.TestResult):
 
         ":param datetime: A datetime.datetime object.
         """
-        time = a_datetime.astimezone(iso8601.Utc())
+        time = a_datetime.astimezone(iso8601.UTC)
         self._stream.write(_b("time: %04d-%02d-%02d %02d:%02d:%02d.%06dZ\n" % (
             time.year, time.month, time.day, time.hour, time.minute,
             time.second, time.microsecond)))
diff --git a/python/subunit/_output.py b/python/subunit/_output.py
index 8141dc9..48a6f7e 100644
--- a/python/subunit/_output.py
+++ b/python/subunit/_output.py
@@ -19,7 +19,7 @@ from functools import partial
 from optparse import OptionGroup, OptionParser, OptionValueError
 
 from subunit import make_stream_binary
-from subunit.iso8601 import UTC
+from iso8601 import UTC
 from subunit.v2 import StreamResultToBytes
 
 _FINAL_ACTIONS = frozenset([
diff --git a/python/subunit/iso8601.py b/python/subunit/iso8601.py
deleted file mode 100644
index fa42270..0000000
--- a/python/subunit/iso8601.py
+++ /dev/null
@@ -1,128 +0,0 @@
-# Copyright (c) 2007 Michael Twomey
-#
-# Permission is hereby granted, free of charge, to any person obtaining a
-# copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be included
-# in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-"""ISO 8601 date time string parsing
-
-Basic usage:
->>> import iso8601
->>> iso8601.parse_date("2007-01-25T12:00:00Z")
-datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.iso8601.Utc ...>)
->>>
-
-"""
-
-import re
-from datetime import datetime, timedelta, tzinfo
-
-__all__ = ["parse_date", "ParseError"]
-
-# Adapted from http://delete.me.uk/2005/03/iso8601.html
-ISO8601_REGEX_PATTERN = (r"(?P<year>[0-9]{4})(-(?P<month>[0-9]{1,2})(-(?P<day>[0-9]{1,2})"
-    r"((?P<separator>.)(?P<hour>[0-9]{2}):(?P<minute>[0-9]{2})(:(?P<second>[0-9]{2})(\.(?P<fraction>[0-9]+))?)?"
-    r"(?P<timezone>Z|(([-+])([0-9]{2}):([0-9]{2})))?)?)?)?"
-)
-TIMEZONE_REGEX_PATTERN = "(?P<prefix>[+-])(?P<hours>[0-9]{2}).(?P<minutes>[0-9]{2})"
-ISO8601_REGEX = re.compile(ISO8601_REGEX_PATTERN.encode('utf8'))
-TIMEZONE_REGEX = re.compile(TIMEZONE_REGEX_PATTERN.encode('utf8'))
-
-zulu = "Z".encode('latin-1')
-minus = "-".encode('latin-1')
-
-class ParseError(Exception):
-    """Raised when there is a problem parsing a date string"""
-
-# Yoinked from python docs
-ZERO = timedelta(0)
-class Utc(tzinfo):
-    """UTC
-
-    """
-    def utcoffset(self, dt):
-        return ZERO
-
-    def tzname(self, dt):
-        return "UTC"
-
-    def dst(self, dt):
-        return ZERO
-UTC = Utc()
-
-class FixedOffset(tzinfo):
-    """Fixed offset in hours and minutes from UTC
-
-    """
-    def __init__(self, offset_hours, offset_minutes, name):
-        self.__offset = timedelta(hours=offset_hours, minutes=offset_minutes)
-        self.__name = name
-
-    def utcoffset(self, dt):
-        return self.__offset
-
-    def tzname(self, dt):
-        return self.__name
-
-    def dst(self, dt):
-        return ZERO
-
-    def __repr__(self):
-        return "<FixedOffset %r>" % self.__name
-
-def parse_timezone(tzstring, default_timezone=UTC):
-    """Parses ISO 8601 time zone specs into tzinfo offsets
-
-    """
-    if tzstring == zulu:
-        return default_timezone
-    # This isn't strictly correct, but it's common to encounter dates without
-    # timezones so I'll assume the default (which defaults to UTC).
-    # Addresses issue 4.
-    if tzstring is None:
-        return default_timezone
-    m = TIMEZONE_REGEX.match(tzstring)
-    prefix, hours, minutes = m.groups()
-    hours, minutes = int(hours), int(minutes)
-    if prefix == minus:
-        hours = -hours
-        minutes = -minutes
-    return FixedOffset(hours, minutes, tzstring)
-
-def parse_date(datestring, default_timezone=UTC):
-    """Parses ISO 8601 dates into datetime objects
-
-    The timezone is parsed from the date string. However it is quite common to
-    have dates without a timezone (not strictly correct). In this case the
-    default timezone specified in default_timezone is used. This is UTC by
-    default.
-    """
-    if not isinstance(datestring, bytes):
-        raise ParseError("Expecting bytes %r" % datestring)
-    m = ISO8601_REGEX.match(datestring)
-    if not m:
-        raise ParseError("Unable to parse date string %r" % datestring)
-    groups = m.groupdict()
-    tz = parse_timezone(groups["timezone"], default_timezone=default_timezone)
-    if groups["fraction"] is None:
-        groups["fraction"] = 0
-    else:
-        groups["fraction"] = int(float("0.%s" % groups["fraction"].decode()) * 1e6)
-    return datetime(int(groups["year"]), int(groups["month"]), int(groups["day"]),
-        int(groups["hour"]), int(groups["minute"]), int(groups["second"]),
-        int(groups["fraction"]), tz)
diff --git a/python/subunit/test_results.py b/python/subunit/test_results.py
index 71a983c..be081c1 100644
--- a/python/subunit/test_results.py
+++ b/python/subunit/test_results.py
@@ -24,6 +24,7 @@ from testtools import StreamResult
 from testtools.content import TracebackContent, text_content
 from testtools.testcase import PlaceHolder
 
+import iso8601
 import subunit
 from subunit import iso8601
 
@@ -193,7 +194,7 @@ class AutoTimingTestResultDecorator(HookedTestResultDecorator):
         time = self._time
         if time is not None:
             return
-        time = datetime.datetime.utcnow().replace(tzinfo=iso8601.Utc())
+        time = datetime.datetime.utcnow().replace(tzinfo=iso8601.UTC)
         self.decorated.time(time)
 
     def progress(self, offset, whence):
diff --git a/python/subunit/tests/test_output_filter.py b/python/subunit/tests/test_output_filter.py
index 0501f79..555d70a 100644
--- a/python/subunit/tests/test_output_filter.py
+++ b/python/subunit/tests/test_output_filter.py
@@ -22,6 +22,8 @@ from functools import partial
 from io import BytesIO, StringIO, TextIOWrapper
 from tempfile import NamedTemporaryFile
 
+from iso8601 import UTC
+
 from testtools import TestCase
 from testtools.compat import _u
 from testtools.matchers import (Equals, Matcher, MatchesAny, MatchesListwise,
@@ -31,7 +33,6 @@ from testtools.testresult.doubles import StreamResult
 import subunit._output as _o
 from subunit._output import (_ALL_ACTIONS, _FINAL_ACTIONS,
                              generate_stream_results, parse_arguments)
-from subunit.iso8601 import UTC
 from subunit.v2 import ByteStreamToStreamResult, StreamResultToBytes
 
 
diff --git a/python/subunit/tests/test_subunit_filter.py b/python/subunit/tests/test_subunit_filter.py
index a3baa5c..508a5df 100644
--- a/python/subunit/tests/test_subunit_filter.py
+++ b/python/subunit/tests/test_subunit_filter.py
@@ -27,9 +27,10 @@ from testtools import TestCase
 from testtools.compat import _b
 from testtools.testresult.doubles import ExtendedTestResult, StreamResult
 
+import iso8601
 import subunit
-from subunit import ByteStreamToStreamResult, StreamResultToBytes, iso8601
-from subunit.test_results import TestResultFilter, make_tag_filter
+from subunit.test_results import make_tag_filter, TestResultFilter
+from subunit import ByteStreamToStreamResult, StreamResultToBytes
 
 
 class TestTestResultFilter(TestCase):
diff --git a/python/subunit/tests/test_test_protocol.py b/python/subunit/tests/test_test_protocol.py
index a40591e..7ad28d2 100644
--- a/python/subunit/tests/test_test_protocol.py
+++ b/python/subunit/tests/test_test_protocol.py
@@ -39,8 +39,9 @@ except ImportError:
 
 from testtools.matchers import Contains, Equals, MatchesAny
 
+import iso8601
+
 import subunit
-import subunit.iso8601 as iso8601
 from subunit.tests import (_remote_exception_repr,
                            _remote_exception_repr_chunked,
                            _remote_exception_str,
@@ -981,7 +982,7 @@ class TestTestProtocolServerStreamTime(unittest.TestCase):
         self.assertEqual(_b(""), self.stream.getvalue())
         self.assertEqual([
             ('time', datetime.datetime(2001, 12, 12, 12, 59, 59, 0,
-            iso8601.Utc()))
+            iso8601.UTC))
             ], self.result._events)
 
 
@@ -1386,7 +1387,7 @@ class TestTestProtocolClient(TestCase):
     def test_time(self):
         # Calling time() outputs a time signal immediately.
         self.protocol.time(
-            datetime.datetime(2009,10,11,12,13,14,15, iso8601.Utc()))
+            datetime.datetime(2009,10,11,12,13,14,15, iso8601.UTC))
         self.assertEqual(
             _b("time: 2009-10-11 12:13:14.000015Z\n"),
             self.io.getvalue())
diff --git a/python/subunit/tests/test_test_protocol2.py b/python/subunit/tests/test_test_protocol2.py
index 4f0eb9f..ef88092 100644
--- a/python/subunit/tests/test_test_protocol2.py
+++ b/python/subunit/tests/test_test_protocol2.py
@@ -32,7 +32,7 @@ from testtools.testresult.doubles import StreamResult
 from testtools.tests.test_testresult import TestStreamResultContract
 
 import subunit
-import subunit.iso8601 as iso8601
+import iso8601
 
 CONSTANT_ENUM = b'\xb3)\x01\x0c\x03foo\x08U_\x1b'
 CONSTANT_INPROGRESS = b'\xb3)\x02\x0c\x03foo\x8e\xc1-\xb5'
@@ -218,7 +218,7 @@ class TestStreamResultToBytes(TestCase):
 
     def test_timestamp(self):
         timestamp = datetime.datetime(2001, 12, 12, 12, 59, 59, 45,
-            iso8601.Utc())
+            iso8601.UTC)
         result, output = self._make_result()
         result.status(test_id="bar", test_status='success', timestamp=timestamp)
         self.assertEqual(CONSTANT_TIMESTAMP, output.getvalue())
@@ -382,7 +382,7 @@ class TestByteStreamToStreamResult(TestCase):
 
     def test_timestamp(self):
         timestamp = datetime.datetime(2001, 12, 12, 12, 59, 59, 45,
-            iso8601.Utc())
+            iso8601.UTC)
         self.check_event(CONSTANT_TIMESTAMP,
             'success', test_id='bar', timestamp=timestamp)
 
diff --git a/python/subunit/tests/test_test_results.py b/python/subunit/tests/test_test_results.py
index 765454a..fc14133 100644
--- a/python/subunit/tests/test_test_results.py
+++ b/python/subunit/tests/test_test_results.py
@@ -26,7 +26,7 @@ from testtools.content import TracebackContent, text_content
 from testtools.testresult.doubles import ExtendedTestResult
 
 import subunit
-import subunit.iso8601 as iso8601
+import iso8601
 import subunit.test_results
 
 
@@ -174,7 +174,7 @@ class TestAutoTimingTestResultDecorator(unittest.TestCase):
     def test_calling_time_inhibits_automatic_time(self):
         # Calling time() outputs a time signal immediately and prevents
         # automatically adding one when other methods are called.
-        time = datetime.datetime(2009,10,11,12,13,14,15, iso8601.Utc())
+        time = datetime.datetime(2009,10,11,12,13,14,15, iso8601.UTC)
         self.result.time(time)
         self.result.startTest(self)
         self.result.stopTest(self)
@@ -182,7 +182,7 @@ class TestAutoTimingTestResultDecorator(unittest.TestCase):
         self.assertEqual(time, self.decorated._calls[0])
 
     def test_calling_time_None_enables_automatic_time(self):
-        time = datetime.datetime(2009,10,11,12,13,14,15, iso8601.Utc())
+        time = datetime.datetime(2009,10,11,12,13,14,15, iso8601.UTC)
         self.result.time(time)
         self.assertEqual(1, len(self.decorated._calls))
         self.assertEqual(time, self.decorated._calls[0])
diff --git a/python/subunit/v2.py b/python/subunit/v2.py
index d344aff..9619f3c 100644
--- a/python/subunit/v2.py
+++ b/python/subunit/v2.py
@@ -23,7 +23,7 @@ import sys
 import zlib
 
 import subunit
-import subunit.iso8601 as iso8601
+import iso8601
 
 utf_8_decode = codecs.utf_8_decode
 
@@ -46,7 +46,7 @@ FLAG_TAGS = 0x0080
 FLAG_MIME_TYPE = 0x0020
 FLAG_EOF = 0x0010
 FLAG_FILE_CONTENT = 0x0040
-EPOCH = datetime.datetime.utcfromtimestamp(0).replace(tzinfo=iso8601.Utc())
+EPOCH = datetime.datetime.utcfromtimestamp(0).replace(tzinfo=iso8601.UTC)
 NUL_ELEMENT = b'\0'[0]
 # Contains True for types for which 'nul in thing' falsely returns false.
 _nul_test_broken = {}
diff --git a/setup.py b/setup.py
index 7bb270a..7938e75 100755
--- a/setup.py
+++ b/setup.py
@@ -59,6 +59,7 @@ setup(
     package_dir={'subunit': 'python/subunit'},
     python_requires=">=3.7",
     install_requires=[
+        'iso8601',
         'testtools>=0.9.34',
     ],
     entry_points={