Variables

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Lab

This is the original contents of the lab file (../labs/01-variables/01-variables.lab.sh).

Follow the instructions in the file to solve the lab.

# This function accepts a "string" of characters passed to the function as input
# An "argument" or "parameter" passed to a function gets a positional parameter variable
# This function should "return" with a "return code" of "2" if the string is empty
sobash_assert_variable_is_not_empty() {

  local string

  string="$1"

  # Replace "$what_goes_here" with the appropriate content
  if [[ "$what_goes_here" == "" ]]; then
    echo -e "\n[FAIL] String is empty." 1>&2
    return 2
  else
    echo -e "\n[INFO] String is not empty."
    return 0
  fi

}


# This function should "return" with a "return code" of "2" if the string is NOT empty
sobash_assert_variable_is_empty() {

  local string

  string="$1"

  # Replace "??" below with the appropriate comparison operator
  if [[ "$string" ?? "" ]]; then
    echo -e "\n[INFO] String is not empty." 1>&2
    return 2
  else
    echo -e "\n[INFO] String is empty."
    return 0
  fi

}

Test

This is the original contents of the test file (../labs/01-variables/01-variables.test.sh).

Review the test cases and your lab file.

Will the lab file (../labs/01-variables/01-variables.lab.sh) pass all test cases?

#!/usr/bin/env bash

test_assert_variable_is_not_empty() {

   declare MY_NOT_EMPTY_VARIABLE
   MY_NOT_EMPTY_VARIABLE="this variable has a value"
   export MY_NOT_EMPTY_VARIABLE
   ../build/sobash assert-variable-is-not-empty MY_NOT_EMPTY_VARIABLE
   assertEquals 0 $?

}


test_assert_variable_is_empty() {

   # No $1 passed to function
   ../build/sobash assert-variable-is-empty
   assertEquals 0 $?

}

source ./shunit2

When ready, run the following to execute the tests above against the lab file:

cd "${HOME}/bash-programming/src/" \ 
  && ./test.sh lab 01-variables

Solution

This is the original contents of the solution file (../labs/01-variables/01-variables.solution.sh).

This file contains an example of a viable solution that passes all the test cases.

sobash_assert_variable_is_not_empty() {

  local string

  string="$1"

  if [[ "$string" == "" ]]; then
    echo -e "\n[FAIL] String is empty." 1>&2
    return 2
  else
    echo -e "\n[INFO] String is not empty."
    return 0
  fi

}

sobash_assert_variable_is_empty() {

  local string

  string="$1"

  if [[ "$string" != "" ]]; then
    echo -e "\n[INFO] String is not empty." 1>&2
    return 2
  else
    echo -e "\n[INFO] String is empty."
    return 0
  fi

}

Run the following to execute the tests above against the solution file:

cd "${HOME}/bash-programming/src/" \ 
  && ./test.sh solution 01-variables

Feel free to run the following to override the contents of the lab file with the solution file.

cd "${HOME}/bash-programming/labs/" \ 
  && cp ./01-variables/01-variables.{solution,lab}.sh