test: fix mock to actually exercise orphan branch path

apps/api/tests/unit/test_git_repository_working_clones.py

@@ -48,11 +48,17 @@ def test_init_working_repository_falls_back_to_symbolic_ref() -> None:
 
 
 def test_create_branch_uses_orphan_checkout_when_head_is_unborn() -> None:
-    verify_head = Mock(returncode=128, stderr="fatal: Needed a single revision")
-    checkout_orphan = Mock(returncode=0, stderr="")
+    call_count = 0
 
-    with patch("src.utils.git_control._run_git_command", side_effect=[verify_head, checkout_orphan]) as run_mock:
+    def mock_run(repo_path: str, *args: str) -> str:
+        nonlocal call_count
+        call_count += 1
+        if call_count == 1:
+            raise RuntimeError("fatal: Needed a single revision")
+        return ""
+
+    with patch("src.utils.git_control._run_git_command", side_effect=mock_run) as run_mock:
         create_branch("/tmp/new-repo", "feature/test")
 
-    assert run_mock.call_args_list[0].args[1:] == ("rev-parse", "--verify", "HEAD")
+    assert run_mock.call_args_list[0].args[1:] == ("rev-parse", "--verify", "HEAD^{commit}")
     assert run_mock.call_args_list[1].args[1:] == ("checkout", "--orphan", "feature/test")