Properly apt-get install inn2 in a GitHub Action.

Demonstrate how to properly `apt-get install inn2` in a GitHub Action.
Configure the inn2 instance so that other code can test interactions with the inn2 server.

Much of this project's documentation covers how to build inn2 from source.  It would be helpful if there were working examples of how to `apt-get install inn2` in Docker or in a GitHub Action.  I have been struggling to do so for a few hours without success.

.github/workflows/atp-get_install_inn2.yaml

@@ -0,0 +1,72 @@
+# Demonstrate how to properly `apt-get install inn2` in a GitHub Action.
+# Configure the inn2 instance so that other code can test interactions with the inn2 server.
+
+name: InterNetNews2
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+jobs:
+  inn2:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: cat "localhost.localdomain" > /etc/hostname
+        run: |
+          echo "localhost.localdomain" > hostname
+          sudo mv hostname /etc/
+          cat /etc/hostname
+      # The next commands usually pass but not always!!!
+      - run: |
+          sudo apt-get update -qq
+          sudo apt-get install --yes inn2
+      # - run: cat /etc/news/inn.conf  # Useful for debugging
+      - run: systemctl status inn2
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: 3.12  # nntplib was removed from the Standard Library in Python 3.13.
+
+      - name: nntplib_demo
+        shell: python
+        run: |
+          import nntplib  # Removed from the Standard Library in Python 3.13.
+          import pathlib
+          with nntplib.NNTP("localhost", readermode=True) as nntp_server:
+              print(f"{nntp_server = }")
+              # print(f"{nntp_server.starttls() = }")  # nntplib.NNTPTemporaryError: 401 MODE-READER
+              print(f"{nntp_server.nntp_version = }")
+              print(f"{nntp_server.nntp_implementation = }")
+              print(f"{nntp_server.getwelcome() = }")
+              print(f"{nntp_server.getcapabilities() = }")
+              print(f"{nntp_server.list() = }")
+              print("News group list:")
+              print("\n".join(
+                  f"{i}. {group_info.group}" for i, group_info in enumerate(nntp_server.list()[1], 1)
+              ))
+              # Ensure the 'local.test' group has no articles.
+              resp, count, first, last, name = nntp_server.group('local.test')
+              print(f"Group '{name}' has {count} articles, range {first} to {last}.")
+              # Post an article to the 'local.test' group.
+              msg = pathlib.Path("contrib/inn_article_001.txt").read_text()
+              # print(f"{msg = }")
+              response = nntp_server.post(msg.encode("utf-8"))
+              print(f"{response = }")
+              # Verify that the article is there.
+              resp, count, first, last, name = nntp_server.group('local.test')
+              print(f"Group '{name}' has {count} articles, range {first} to {last}.")
+              # Read the article.
+              stat = nntp_server.stat()  # last() and next() both fail
+              # print(f"{stat = }")
+              article = nntp_server.article(stat[2])
+              print(f"{article = }")
+              # Print the lines of the article
+              print("\n".join(line.decode("utf-8") for line in article[1].lines))
+              # Print the overview information
+              resp, count, first, last, name = nntp_server.group('local.test')
+              # print(resp, count, first, last, name)
+              resp, overviews = nntp_server.over((first, last))
+              for id, over in overviews:
+                  print(id, nntplib.decode_header(over['subject']))

contrib/inn_article_001.txt

@@ -0,0 +1,6 @@
+From: GitHub Actions <[email protected]>
+Newsgroups: local.test
+Subject: inews test
+Message-ID: <[email protected]>
+
+This is a test message posted to the local.test group.

support/mkmanifest

@@ -71,6 +71,7 @@ __DATA__
 
 # The following additional files should be ignored.  The file names are
 # relative to the root of the tree.  Shell wildcards are supported.
+.github/workflows/atp-get_install_inn2.yaml
 BOOTSTRAP
 LIST.*
 Makefile.global
@@ -123,6 +124,7 @@ contrib/count_overview
 contrib/expirectl
 contrib/findreadgroups
 contrib/fixhist
+contrib/inn_article_001.txt
 contrib/innconfcheck
 contrib/makeexpctl
 contrib/makestorconf