Bash and Test-Driven Development

Question

When writing more than a trivial script in bash, I often wonder how to make the code testable.

It is typically hard to write tests for bash code, due to the fact tha

Answer 1

The advanced bash scripting guide has an example of an assert function but here is a simpler and more flexible assert function - just use eval of $* to test any condition.

assert() {
  if ! eval $* ; then
      echo
      echo "===== Assertion failed:  \"$*\" ====="
      echo "File \"$0\", line:$LINENO line:${BASH_LINENO[*]}"
      echo line:$(caller 0)
      exit 99
  fi  
}

# e.g. USAGE:
assert [[ $r == 42 ]]
assert "((r==42))"

BASH_LINENO and caller bash builtin are bash shell specific.