### What this PR does / why we need it? Install doctest ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? CI passed Related: https://github.com/vllm-project/vllm-ascend/pull/983 Co-authored-by: wangli <wangli858794774@gmail.com> Signed-off-by: Yikun Jiang <yikunkero@gmail.com> Co-authored-by: wangli <wangli858794774@gmail.com>