[PATCH b4 v2 27/44] tests: pin the default branch in the queue-delivery fixture

The fixture pushes to refs/heads/master but creates the bare
repository with a plain "git init --bare", so any other
init.defaultBranch leaves the clone on an unborn branch and the test
fails during setup. Name the initial branch.

Signed-off-by: Christian Brauner (Amutable) <[email protected]>
---
 src/tests/test_ty.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/tests/test_ty.py b/src/tests/test_ty.py
index 968d672..8ca5184 100644
--- a/src/tests/test_ty.py
+++ b/src/tests/test_ty.py
@@ -355,7 +355,10 @@ def test_commit_reachable_unknown_tips(
     pub = str(tmp_path / 'pub')
     other = str(tmp_path / 'other')
     _init_repo(local)
-    ecode, out = b4.git_run_command(None, ['init', '--bare', pub])
+    # -b master: the clone below takes its HEAD from this repository, and an
+    # init.defaultBranch of 'main' would leave it on an unborn branch, with
+    # the "advance the remote" commit landing as an unrelated root commit.
+    ecode, out = b4.git_run_command(None, ['init', '--bare', '-b', 'master', pub])
     assert ecode == 0, out
     monkeypatch.chdir(local)
     c1 = _commit_empty('c1')

-- 
2.53.0