UN-4522 [MISC] Release branching V2: port release-line workflows

.github/release/ruff.toml

@@ -0,0 +1,7 @@
+# The repo's ruff settings, plus the release tooling's own style: short local lambdas, `l` for a label, and tests
+# that set GITHUB_REPOSITORY before importing relstate.
+extend = "../../pyproject.toml"
+
+[lint.extend-per-file-ignores]
+"*.py" = ["E731", "E741"]
+"test_*.py" = ["E402"]

.github/release/test_links.py

@@ -0,0 +1,41 @@
+import os
+import unittest
+from unittest import mock
+
+import relmgr as rm
+
+ACTIONS = {
+    "GITHUB_SERVER_URL": "https://github.com",
+    "GITHUB_REPOSITORY": "Zipstack/example",
+    "RELSTATE_AR_ON_PREM": "projects/p/locations/l/repositories/r",
+}
+WEB = "https://github.com/Zipstack/example"
+SHA = "6635951" + "0" * 33
+
+
+class Links(unittest.TestCase):
+    def test_actions(self):
+        with mock.patch.dict(os.environ, ACTIONS):
+            self.assertEqual(rm.pr_link(246), f"[#246]({WEB}/pull/246)")
+            self.assertEqual(rm.commit_link(SHA), f"[`6635951`]({WEB}/commit/{SHA})")
+            self.assertEqual(
+                rm.tag_link("v0.192.0-rc.1"),
+                f"[`v0.192.0-rc.1`]({WEB}/releases/tag/v0.192.0-rc.1)",
+            )
+            self.assertEqual(
+                rm.image_link("on-prem", "v0.192.0-rc.1"),
+                "[`on-prem:v0.192.0-rc.1`](https://console.cloud.google.com/artifacts/docker/p/l/r)",
+            )
+
+    def test_plain_outside_actions(self):
+        with mock.patch.dict(os.environ, clear=True):
+            self.assertEqual(rm.pr_link(246), "#246")
+            self.assertEqual(rm.commit_link(SHA), "`6635951`")
+            self.assertEqual(rm.tag_link("v0.192.0-rc.1"), "`v0.192.0-rc.1`")
+            self.assertEqual(
+                rm.image_link("cloud", "v0.192.0-rc.1"), "`cloud:v0.192.0-rc.1`"
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()