Script testing strategies in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of a simple test function in bash

What is the output of this bash script when run in a terminal?

Bash Scripting

#!/bin/bash

test_function() {
  if [ "$1" -gt 10 ]; then
    echo "Greater"
  else
    echo "Smaller or equal"
  fi
}

result=$(test_function 15)
echo "$result"

A Smaller or equal

B Greater

C 15

D Syntax error

💡 Hint

Look at the condition inside the function and the argument passed.

The function checks if the input argument is greater than 10. Since 15 is greater than 10, it prints 'Greater'.

🧠 Conceptual

intermediate

Purpose of exit codes in bash script testing

Why are exit codes important when testing bash scripts?

A They change the script's output text automatically

B They prevent the script from running if errors occur

C They indicate success or failure of commands, helping automate test checks

D They format the script's output for readability

💡 Hint

Think about how scripts communicate results to other programs or tests.

Exit codes are numbers returned by commands or scripts to indicate success (usually 0) or failure (non-zero). Test scripts use these codes to decide if a test passed or failed.

🔧 Debug

advanced

Identify the error in this test script snippet

What error will this bash script produce when run?

Bash Scripting

#!/bin/bash

check_file() {
  if [ -f $1 ]; then
    echo "File exists"
  else
    echo "File missing"
  fi
}

check_file "/tmp/testfile"

A No error, outputs 'File exists' or 'File missing'

B Syntax error due to missing quotes around $1 in the if condition

C Runtime error: command not found

D Outputs nothing

💡 Hint

Check if the script handles file path arguments correctly.

The script correctly checks if the file exists using -f and prints the appropriate message. Quotes around $1 are recommended but not mandatory here.

🚀 Application

advanced

Automate testing of a script output

You want to test if your script 'hello.sh' outputs exactly 'Hello World!'. Which command correctly tests this and returns exit code 0 if it matches?

A if ./hello.sh | grep -q 'Hello World'; then echo 'Test failed'; else echo 'Test passed'; fi

B if ./hello.sh | grep 'Hello'; then echo 'Test passed'; else echo 'Test failed'; fi

C if ./hello.sh | grep -v 'Hello World!'; then echo 'Test passed'; else echo 'Test failed'; fi

D if ./hello.sh | grep -q '^Hello World!$'; then echo 'Test passed'; else echo 'Test failed'; fi

💡 Hint

Use grep with exact match anchors and quiet mode to check output.

Option D uses grep with ^ and $ anchors to match the exact output and -q to suppress output, making it suitable for testing exact output.

🧠 Conceptual

expert

Best practice for isolating tests in bash scripts

Which approach best isolates tests to avoid side effects when running multiple bash script tests?

A Run each test in a separate subshell or temporary environment

B Run all tests sequentially in the same shell without resetting variables

C Use global variables to share state between tests

D Run tests only once to avoid repeated side effects

💡 Hint

Think about how to keep tests independent and avoid interference.

Running tests in subshells or temporary environments prevents changes in one test from affecting others, ensuring reliable and repeatable results.