From 67dac76a74e32f645faa003ee7516b93267de8af Mon Sep 17 00:00:00 2001
From: Santos Gallegos <stsewd@proton.me>
Date: Wed, 3 Sep 2025 15:15:08 -0500
Subject: [PATCH] Versions: more tests for sync versions

---
 .../rtd_tests/tests/test_sync_versions.py     | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/readthedocs/rtd_tests/tests/test_sync_versions.py b/readthedocs/rtd_tests/tests/test_sync_versions.py
index 85ec9c9818e..d7339f28cfa 100644
--- a/readthedocs/rtd_tests/tests/test_sync_versions.py
+++ b/readthedocs/rtd_tests/tests/test_sync_versions.py
@@ -302,6 +302,7 @@ def test_update_latest_version_type(self):
         )
 
         latest_version = self.pip.versions.get(slug=LATEST)
+        self.assertIsNone(self.pip.default_branch)
         self.assertEqual(latest_version.type, BRANCH)
         self.assertEqual(latest_version.identifier, "master")
         self.assertEqual(latest_version.verbose_name, "latest")
@@ -769,12 +770,36 @@ def test_machine_attr_when_user_define_latest_tag_and_delete_it(self):
 
         # The latest isn't stuck with the previous commit
         version_latest = self.pip.versions.get(slug="latest")
+        self.assertIsNone(self.pip.default_branch)
+        self.assertTrue(version_latest.machine)
         self.assertEqual(
             "master",
             version_latest.identifier,
         )
         self.assertTrue(version_latest.machine)
 
+        # Test with an explicit default branch (tag).
+        self.pip.default_branch = "default-tag"
+        self.pip.save()
+
+        tags_data = [
+            {
+                "identifier": "1abc2def3",
+                "verbose_name": "default-tag",
+            }
+        ]
+
+        sync_versions_task(
+            self.pip.pk,
+            branches_data=branches_data,
+            tags_data=tags_data,
+        )
+
+        version_latest = self.pip.versions.get(slug="latest")
+        self.assertTrue(version_latest.machine)
+        self.assertEqual(version_latest.identifier, "default-tag")
+        self.assertEqual(version_latest.type, TAG)
+
     def test_machine_attr_when_user_define_latest_branch_and_delete_it(self):
         """The user creates a branch named ``latest`` on an existing repo, when
         syncing the versions, the RTD's ``latest`` is lost (set to
@@ -802,6 +827,8 @@ def test_machine_attr_when_user_define_latest_branch_and_delete_it(self):
 
         # The branch is the new latest
         version_latest = self.pip.versions.get(slug="latest")
+        self.assertIsNone(self.pip.default_branch)
+        self.assertFalse(version_latest.machine)
         self.assertEqual(
             "origin/latest",
             version_latest.identifier,
@@ -823,12 +850,38 @@ def test_machine_attr_when_user_define_latest_branch_and_delete_it(self):
 
         # The latest isn't stuck with the previous branch
         version_latest = self.pip.versions.get(slug="latest")
+        self.assertIsNone(self.pip.default_branch)
+        self.assertTrue(version_latest.machine)
         self.assertEqual(
             "master",
             version_latest.identifier,
         )
         self.assertTrue(version_latest.machine)
 
+        # Test with an explicit default branch.
+        branches_data = [
+            {
+                "identifier": "origin/master",
+                "verbose_name": "master",
+            },
+            {
+                "identifier": "origin/default-branch",
+                "verbose_name": "default-branch",
+            },
+        ]
+        self.pip.default_branch = "default-branch"
+        self.pip.save()
+        sync_versions_task(
+            self.pip.pk,
+            branches_data=branches_data,
+            tags_data=[],
+        )
+
+        version_latest = self.pip.versions.get(slug="latest")
+        self.assertTrue(version_latest.machine)
+        self.assertEqual(version_latest.identifier, "default-branch")
+        self.assertEqual(version_latest.type, BRANCH)
+
     def test_deletes_version_with_same_identifier(self):
         branches_data = [
             {