if-statements

#!/usr/bin/env bash
#
# shellcheck disable=SC2016
#
# The point of this script is to show the difference between the different kinds of if
# and test statements, and how they behave differently when dealing with different kinds
# variables.
#
########################################################################################
#### [ Setup ]


a=true
b=false
c="cat"
#d="does_not_exist" <- DO NOT UNCOMMENT THIS LINE

echo "
----------------------------------
| Value of variables:            |
| a=true                         |
| b=false                        |
| c='cat'                        |
| # d is a non-existent variable |
----------------------------------
"


#### End of [ Setup ]
########################################################################################
#### [ Testing if statements ]


# True if ==> $a is true
# Produce ==> true
printf 'if "$a"'
if "$a"; then echo ' => true'
else          echo ' => false'
fi

# True if ==> $b is true
# Produce ==> false
printf 'if "$b"'
if "$b"; then echo ' => true'
else          echo ' => false'
fi

# True if ==> DOES NOT WORK...
# Produce ==> DOES NOT WORK ...
#printf 'if "$c"'
#if "$c"; then echo ' => true'
#else          echo ' => false'
#fi

# True if ==> COMMAND NOT FOUND
# Produce ==> COMMAND NOT FOUND
#printf 'if "$d"'
#if "$d"; then echo ' => true'
#else          echo ' => false'
#fi

############################################

# True if ==> $a exists
# Produce ==> true
printf 'if [[ $a ]]'
if [[ $a ]]; then echo ' => true'
else              echo ' => false'
fi

# True if ==> $b exists
# Produce ==> true
printf 'if [[ $b ]]'
if [[ $b ]]; then echo ' => true'
else              echo ' => false'
fi

# True if ==> $c exists
# Produce ==> true
printf 'if [[ $c ]]'
if [[ $c ]]; then echo ' => true'
else              echo ' => false'
fi

# True if ==> $d exists
# Produce ==> false
printf 'if [[ $d ]]'
if [[ $d ]]; then echo ' => true'
else              echo ' => false'
fi

############################################

# True if ==> $a is true
# Produce ==> true
printf 'if [[ $a = true ]]'
if [[ $a = true ]]; then echo ' => true'
else                     echo ' => false'
fi

# True if ==> $b is true
# Produce ==> false
printf 'if [[ $b = true ]]'
if [[ $b = true ]]; then echo ' => true'
else                     echo ' => false'
fi

# True if ==> $c is true
# Produce ==> false
printf 'if [[ $c = true ]]'
if [[ $c = true ]]; then echo ' => true'
else                     echo ' => false'
fi

# True if ==> $d is true
# Produce ==> false
printf 'if [[ $d = true ]]'
if [[ $d = true ]]; then echo ' => true'
else                     echo ' => false'
fi

############################################

# True if ==> $a is true
# Produce ==> true
printf '"$a" &&'
"$a" && echo ' => true' || echo ' => false'

# True if ==> $b is true
# Produce ==> false
printf '"$b" &&'
"$b" && echo ' => true' || echo ' => false'

# True if ==> DOES NOT WORK...
# Produce ==> DOES NOT WORK...
#printf '"$c" &&'
#"$c" && echo ' => true' || echo ' => false'

# True if ==> COMMAND NOT FOUND
# Produce ==> COMMAND NOT FOUND
#printf '"$d" &&'
#"$d" && echo ' => true' || echo ' => false'

############################################

# True if ==> $a exists
# Produce ==> true
printf '[[ $a ]] &&'
[[ $a ]] && echo ' => true' || echo ' => false'

# True if ==> $b exists
# Produce ==> true
printf '[[ $b ]] &&'
[[ $b ]] && echo ' => true' || echo ' => false'

# True if ==> $c exists
# Produce ==> true
printf '[[ $c ]] &&'
[[ $c ]] && echo ' => true' || echo ' => false'

# True if ==> $c exists
# Produce ==> false
printf '[[ $d ]] &&'
[[ $d ]] && echo ' => true' || echo ' => false'

############################################

# True if ==> $a is true
# Produce ==> true
printf '[[ $a = true ]] &&'
[[ $a = true ]] && echo ' => true' || echo ' => false'

# True if ==> $b is true
# Produce ==> false
printf '[[ $b = true ]] &&'
[[ $b = true ]] && echo ' => true' || echo ' => false'

# True if ==> $c is true
# Produce ==> false
printf '[[ $c = true ]] &&'
[[ $c = true ]] && echo ' => true' || echo ' => false'

# True if ==> $d is true
# Produce ==> false
printf '[[ $d = true ]] &&'
[[ $d = true ]] && echo ' => true' || echo ' => false'



#### End of [ Testing if statements ]
########################################################################################

if_statements_spec.sh

# shellcheck shell=bash
#
# The point of this script is to show the difference between the different kinds of if
# and test statements, and how they behave differently when dealing with different kinds
# variables.
#
# The main difference between this script and the other one is that this script uses
# unit tests to test the output of the if statements, and the other script just uses
# simple bash commands to test the output of the if statements. Niether is better than
# the other. I mainly created to get practice with unit testing in bash.
#
# To execute this script, you must have shellspec installed. You can install it by
# following the instructions here: https://github.com/shellspec/shellspec
# Once you have shellspec installed, you can execute the script by running the following
# command: `shellspec --format tap if_statements_spec.sh`
#
########################################################################################
#### [ Functions ]


func_one() {
    # First if statement required to prevent the program from freezing when performing
    # unit test. If you just ran the if statement such that it is 'if "$c"', it'd return
    # a status of 1, because we are attempting to test if the string "cat" is true or
    # false, which is not possible.
    if [[ $1 = "cat" ]]; then
        return 2
    fi

    if "$1"; then
        return 0
    else
        return 1
    fi
}

func_two() {
    # First if statement required to prevent the program from freezing when performing
    # unit test. If you just ran the if statement such that it is 'if "$c"', it'd return
    # a status of 1.
    if [[ $1 = "cat" ]]; then
        return 2
    fi

    "$1" && return 0 || return 1
}


#### End of [ Functions ]
########################################################################################
#### [ Setup ]


a=true
b=false
c="cat"
#d="does_not_exist" <- DO NOT UNCOMMENT THIS LINE

echo "
----------------------------------
| Value of variables:            |
| a=true                         |
| b=false                        |
| c='cat'                        |
| # d is a non-existent variable |
----------------------------------
"


#### End of [ Setup ]
########################################################################################
#### [ Testing if statements ]


Describe "When the if statement is 'if"
    It "\"\$a\"', the output is 'true'"
        When call func_one "$a"
        The status should eq 0
    End

    It "\"\$b\"', the output is 'false'"
        When call func_one "$b"
        The status should eq 1
    End

    It "\"\$c\"', the output is 'false'"
        When call func_one "$c"
        The status should eq 2
    End

    It "\"\$d\"', the output should include 'command not found'"
        When call func_one "$d"
        The status should eq 1
        The stderr should include "command not found"
    End
End

Describe "When the if statement is"
    It "'\"\$a\" &&', the output is 'true'"
        When call func_two "$a"
        The status should eq 0
    End

    It "'\"\$b\" &&', the output is 'false'"
        When call func_two "$b"
        The status should eq 1
    End

    It "'\"\$c\" &&', the output is 'false'"
        When call func_two "$c"
        The status should eq 2
    End

    It "'\"\$d\" &&', the output should include 'command not found'"
        When call func_two "$d"
        The status should eq 1
        The stderr should include "command not found"
    End
End


#### End of [ Testing if statements ]
########################################################################################