### What this PR does / why we need it?
add ut for decorator.py/deepseek_mtp.py
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
CI passed with new tests
- vLLM version: v0.10.0
- vLLM main:
055bd3978e
---------
Signed-off-by: CaranLic <740821011@qq.com>
### What this PR does / why we need it?
Add some uts for files in folder /multistream
### Does this PR introduce _any_ user-facing change?
No
- vLLM version: v0.9.2
- vLLM main:
b77c7d327f
Signed-off-by: lwq <liwenquan5@huawei.com>
Co-authored-by: lwq <liwenquan5@huawei.com>