DEVX-17: fix: pass --break-system-packages to pip in CI environments

tests/unit/test_setup.py

@@ -1,5 +1,6 @@
 """Unit tests for devx.tools.setup."""
 
+import os
 import subprocess
 from pathlib import Path
 from unittest.mock import MagicMock, patch
@@ -47,6 +48,12 @@ class TestInstallPythonDeps:
         _install_python_deps(".venv/bin", "ci,lint")
         mock_run.assert_called_once_with([".venv/bin/pip", "install", "-e", ".[ci,lint]"])
 
+    @patch("devx.tools.setup._run")
+    def test_install_with_break_system_packages(self, mock_run: MagicMock) -> None:
+        with patch.dict(os.environ, {"PIP_BREAK_SYSTEM_PACKAGES": "1"}):
+            _install_python_deps(".venv/bin", "ci")
+        mock_run.assert_called_once_with([".venv/bin/pip", "install", "-e", ".[ci]", "--break-system-packages"])
+
 
 class TestInstallPreCommitHooks:
     @patch("devx.tools.setup._run")