Bash script unit testing

Bash scripts are a powerful tool for automating tasks on Linux and Unix-based systems. However, as with any code, it's important to make sure that our scripts are working correctly before deploying them to production. One way to do this is by using unit testing.

Unit testing is a method of testing individual units or components of code, in isolation from the rest of the system. This allows us to catch errors early on and to ensure that our scripts are functioning as expected.

There are several tools available for unit testing bash scripts. One popular option is Bats (Bash Automated Testing System). Bats is a simple testing framework for bash scripts that allows you to write test cases in a simple, human-readable format.

Here's an example of how you might use Bats to test a simple bash script:

 

#!/usr/bin/env bats 

@test "Check if script is executable" {
  run chmod +x myscript.sh
  [ "$status" -eq 0 ]
}

@test "Check if script runs without error" {
  run ./myscript.sh
  [ "$status" -eq 0 ]

}



@test "Check if script produces expected output" {
  run ./myscript.sh
  [ "$output" = "Hello, World!" ]

}

In this example, we're using three different test cases to check different aspects of our script. The first test checks that the script is executable. The second test checks that the script runs without error. And the third test checks that the script produces the expected output.

To run the tests, you simply need to execute the test file:

 $ bats myscript_test.sh

Bats will run all the test cases in the file and display the results in a clear, easy-to-read format. If any of the tests fail, you'll see an error message indicating which test failed and why.

Unit testing is an essential part of software development, and it's no different for bash scripts. By using tools like Bats, you can catch errors early on and ensure that your scripts are working as expected.