bats software package provides bash automated testing system, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install bats
bats is installed in your system.
Make ensure the bats package were installed using the commands given below,
$ sudo dpkg-query -l | grep bats *
You will get with bats package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Shells |
| Package | bats |
| Version | 0.4.0-1.1 |
| Description | bash automated testing system |
| Sub Section | Shells |