diff --git a/pyproject.toml b/pyproject.toml
index c106474..c163c7f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -55,6 +55,7 @@ xontrib-vox = "^0.0.1"
 optional = false
 [tool.poetry.group.dev.dependencies]
 pytest = "^8.2.0"
+pexpect = "^4.9.0"
 
 # only for xonsh as sh..
 xontrib-vox = "^0.0.1"