test: add integration test for zsh bootstrap behavior with non-zero rc return

Author: Akagi201

tests/test_shellflow.py

@@ -13,10 +13,13 @@
 from typing import Any
 from unittest import mock
 
+import os
 import pytest
 from hypothesis import given
 from hypothesis import strategies as st
 
+ZSH_AVAILABLE = os.path.exists("/bin/zsh")
+
 from shellflow import (
     VALID_EXPORT_SOURCES,
     Block,
@@ -833,6 +836,7 @@ def test_no_ssh_config_uses_manual_lookup(
 class TestShellBootstrapIntegration:
     """Integration-style tests for non-interactive shell bootstrap behavior."""
 
+    @pytest.mark.skipif(not ZSH_AVAILABLE, reason="zsh not available")
     def test_zsh_bootstrap_ignores_nonzero_zshrc_and_keeps_path_customizations(self, tmp_path: Path) -> None:
         """Test guarded zshrc bootstrap still exposes commands after a non-zero rc return."""
         bin_dir = tmp_path / "bin"