It's really hard to run pungi tests on Fedora Rawhide, since pungi setup.py and tox.ini omit many dependencies, and some dependencies are simply not available on Python 3.8... I used the following commands:
---
sudo dnf install -y python3-tox libxslt-devel libffi-devel krb5-devel python3-libcomps
git clone https://pagure.io/forks/vstinner/pungi.git
cd pungi
tox -e py38
# tox fails...
ln -s /usr/lib64/python3.7/site-packages/libcomps .tox/py38/lib/python3.8/site-packages/
.tox/py38/bin/python -m pip install nose koji PyYAML
LANG= .tox/py38/bin/nosetests tests/
---

I tried the following change but it doesn't fix the issue:

commit 14a4c33a4baadd77fad7d44fac34dda5c7aa5e40
Author: Victor Stinner <vstinner>
Date:   Wed Apr 17 14:26:29 2019 +0200

    Fix XML serialization on Python 3.8
    
    Python dict keeps insertion order since Python 3.6 and XML
    serialization no longer sort attributes by their name since Python
    3.8. So declare attributes in the order expected by tests (sort by
    name).
    
    Resolves: rhbz#1698514

diff --git a/pungi/dnf_wrapper.py b/pungi/dnf_wrapper.py
index af1d0cb..129b223 100644
--- a/pungi/dnf_wrapper.py
+++ b/pungi/dnf_wrapper.py
@@ -101,7 +101,7 @@ class CompsWrapper(object):
             packages.extend([i.name for i in group.optional_packages])
 
         for package in group.conditional_packages:
-            conditional.append({"name": package.requires, "install": package.name})
+            conditional.append({"install": package.name, "name": package.requires})
 
         return packages, conditional
 
@@ -129,7 +129,7 @@ class CompsWrapper(object):
     def get_langpacks(self):
         result = []
         for name, install in self.comps._i.langpacks.items():
-            result.append({"name": name, "install": install})
+            result.append({"install": install, "name": name})
         return result

Alternatively with the mock config from https://copr.fedorainfracloud.org/coprs/g/python/python3.8/

$ mock -r fedora-rawhide-x86_64-python38.cfg install 'python(abi) = 3.8' python3-devel python3-koji python3-libcomps python3-tox python3-lxml python3-pyyaml git-core
$ mock -r fedora-rawhide-x86_64-python38.cfg --enable-network shell
<mock-chroot> # git clone https://pagure.io/pungi.git
<mock-chroot> # cd pungi/
<mock-chroot> # python3 -m venv --system-site-packages __venv__
<mock-chroot> # . __venv__/bin/activate
(__venv__) <mock-chroot> # pip install nose mock
(__venv__) <mock-chroot> # pip install -e .
(__venv__) <mock-chroot> # nosetests tests/

That gives 258 errors (AttributeError: ... object has no attribute 'assertItemsEqual')

And 2 failures:

======================================================================
FAIL: test_filter_environments (tests.test_comps_wrapper.CompsWrapperTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/pungi/tests/test_comps_wrapper.py", line 85, in test_filter_environments
    self.assertFilesEqual(COMPS_ENVIRONMENT_FILE, self.file.name)
  File "/pungi/tests/helpers.py", line 33, in assertFilesEqual
    self.assertEqual(diff, '', 'Files differ:\n' + diff)
AssertionError: '--- EXPECTED\n\n+++ ACTUAL\n\n@@ -10,7 +1[769 chars]mps>' != ''
Diff is 843 characters long. Set self.maxDiff to None to see it. : Files differ:
--- EXPECTED

+++ ACTUAL

@@ -10,7 +10,7 @@

     <default>true</default>
     <uservisible>true</uservisible>
     <packagelist>
-      <packagereq requires="dummy-imsettings" type="conditional">dummy-imsettings-gnome</packagereq>
+      <packagereq type="conditional" requires="dummy-imsettings">dummy-imsettings-gnome</packagereq>
     </packagelist>
   </group>
   <group>
@@ -99,8 +99,8 @@

     </grouplist>
   </environment>
   <langpacks>
-    <match install="aspell-%s" name="aspell"/>
-    <match install="firefox-langpack-%s" name="firefox"/>
-    <match install="kde-l10n-%s" name="kdelibs"/>
+    <match name="aspell" install="aspell-%s"/>
+    <match name="firefox" install="firefox-langpack-%s"/>
+    <match name="kdelibs" install="kde-l10n-%s"/>
   </langpacks>
 </comps>

======================================================================
FAIL: test_filter_groups (tests.test_comps_wrapper.CompsWrapperTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/pungi/tests/test_comps_wrapper.py", line 70, in test_filter_groups
    self.assertFilesEqual(COMPS_GROUP_FILE, self.file.name)
  File "/pungi/tests/helpers.py", line 33, in assertFilesEqual
    self.assertEqual(diff, '', 'Files differ:\n' + diff)
AssertionError: '--- EXPECTED\n\n+++ ACTUAL\n\n@@ -10,7 +1[769 chars]mps>' != ''
Diff is 843 characters long. Set self.maxDiff to None to see it. : Files differ:
--- EXPECTED

+++ ACTUAL

@@ -10,7 +10,7 @@

     <default>true</default>
     <uservisible>true</uservisible>
     <packagelist>
-      <packagereq requires="dummy-imsettings" type="conditional">dummy-imsettings-gnome</packagereq>
+      <packagereq type="conditional" requires="dummy-imsettings">dummy-imsettings-gnome</packagereq>
     </packagelist>
   </group>
   <group>
@@ -88,8 +88,8 @@

     </grouplist>
   </environment>
   <langpacks>
-    <match install="aspell-%s" name="aspell"/>
-    <match install="firefox-langpack-%s" name="firefox"/>
-    <match install="kde-l10n-%s" name="kdelibs"/>
+    <match name="aspell" install="aspell-%s"/>
+    <match name="firefox" install="firefox-langpack-%s"/>
+    <match name="kdelibs" install="kde-l10n-%s"/>
   </langpacks>
 </comps>

======================================================================
FAIL: test_write_comps (tests.test_comps_wrapper.CompsWrapperTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/pungi/tests/test_comps_wrapper.py", line 60, in test_write_comps
    self.assertFilesEqual(COMPS_FORMATTED_FILE, self.file.name)
  File "/pungi/tests/helpers.py", line 33, in assertFilesEqual
    self.assertEqual(diff, '', 'Files differ:\n' + diff)
AssertionError: '--- EXPECTED\n\n+++ ACTUAL\n\n@@ -10,7 +1[771 chars]mps>' != ''
Diff is 845 characters long. Set self.maxDiff to None to see it. : Files differ:
--- EXPECTED

+++ ACTUAL

@@ -10,7 +10,7 @@

     <default>true</default>
     <uservisible>true</uservisible>
     <packagelist>
-      <packagereq requires="dummy-imsettings" type="conditional">dummy-imsettings-gnome</packagereq>
+      <packagereq type="conditional" requires="dummy-imsettings">dummy-imsettings-gnome</packagereq>
     </packagelist>
   </group>
   <group>
@@ -122,8 +122,8 @@

     </grouplist>
   </environment>
   <langpacks>
-    <match install="aspell-%s" name="aspell"/>
-    <match install="firefox-langpack-%s" name="firefox"/>
-    <match install="kde-l10n-%s" name="kdelibs"/>
+    <match name="aspell" install="aspell-%s"/>
+    <match name="firefox" install="firefox-langpack-%s"/>
+    <match name="kdelibs" install="kde-l10n-%s"/>
   </langpacks>
 </comps>

----------------------------------------------------------------------
Ran 924 tests in 4.146s

FAILED (SKIP=138, errors=258, failures=3)

Thank you for the testing guidance. With this patch [0] I can get all tests passing.

[0]: https://pagure.io/pungi/pull-request/1174

Thanks. Testing in copr build.

Works. Please close this bug once that code is part of the Fedora package. No need to patch the package immediately, we don't plan to move this forward until at least Python 3.8.0 beta 1 (2019-05-26).

The patch is merged and will go out in next release.

New failure with 3.8.0a4:

======================================================================
FAIL: test_validate_dummy_config (tests.test_config_validate_script.ConfigValidateScriptTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/pungi-4.1.36/tests/test_config_validate_script.py", line 30, in test_validate_dummy_config
    self.assertEqual(b'', stderr)
AssertionError: b'' != b'/usr/lib/python3.8/site-packages/requests[441 chars]e.\n'

----------------------------------------------------------------------
Ran 1033 tests in 10.572s

I believe this is some new DeprecationWarning on the stderr messing with the test.

Created attachment 1568974 [details]
Full log from Copr (Python 3.8.8a4)

You're right, the test trips on a warning. The warning is not coming from Pungi code, so I think the best short-term solution is to silence it. That being said, it's definitely a good idea to fix such errors where we can.

PR: https://pagure.io/pungi/pull-request/1192

I currently have this:

+Patch5:         https://pagure.io/pungi/pull-request/1174.patch
+Patch6:         https://pagure.io/pungi/pull-request/1192.patch

And the package builds.

You keep adding new patches to the spec, without applying those. Making me rebase again and again and again.

Could you please add the two patches as well?

Builds now. Thanks.