Experimenting with bash scripts

asserts.sh

#! /bin/sh

# asserts if the correct number of parameters where passed to the function
# first parameter should always be $# which is the original count of parameters
# of the function
# second parameter is the correct number of parameters
# the last parameter is the name of the function which can be hardcoded or ${FUNCNAME[0]} can be used
function assert_argument_count() {
	if [ $1 -ne $2 ]; then
	    echo "Illegal number of parameters '$3' passed $# but $2 needed" >&2
	    exit 2
	fi
}

# asserts if the parameters have equal values
function assert_equals() {
	if [ "$1" == "$2" ]; then
		LAST_ASSERT_PASSED=1
	else
		LAST_ASSERT_PASSED=0
	    echo "FAILED! Expected $2 but got $1" >&2
	    return 1
	fi
}

functions.sh

#! /bin/sh

# Based on the parameter --with-returns the variable __WITH_RETURNS is set properly to 0 or 1
function function_output(){
	assert_argument_count $# 1 ${FUNCNAME[0]}
	if [ ${__WITH_RETURNS:-0} -eq 1 ]; then
		_last_return=$1
	else
		echo $1
	fi
}

source ./functions_string.sh

# Functions needed for the tests
source ./functions_test.sh

functions_string.sh

#! /bin/sh

function strlen() {
	assert_argument_count $# 1 ${FUNCNAME[0]}
	local RETURN_VALUE=${#1}
	function_output $RETURN_VALUE
}

function str_replace() {
	assert_argument_count $# 3 ${FUNCNAME[0]}
	local RETURN_VALUE=${1//$2/$3}
	function_output $RETURN_VALUE
}

function substr() {
	assert_argument_count $# 2 ${FUNCNAME[0]}
	local RETURN_VALUE=${1:$2}
	function_output $RETURN_VALUE
}

functions_test.sh

#! /bin/sh/

function print_test_head(){
	assert_argument_count $# 2 ${FUNCNAME[0]}
	echo "Testing \`$1\` output should be $2"
}
function print_last_result() {
	assert_argument_count $# 0 ${FUNCNAME[0]}
	echo "Output: $_last_return"
}

function start_test(){
	assert_argument_count $# 2 ${FUNCNAME[0]}
	echo "----- TEST START -----"
	print_test_head "$1" "$2"
	if [ ${__WITH_RETURNS:-0} -eq 1 ]; then
		eval $1
	else
		# We fake last return as the output of the function
		_last_return=$($1)
	fi
	assert_equals $_last_return $2
}

function end_test(){
	assert_argument_count $# 0 ${FUNCNAME[0]}
	print_last_result
	echo "----- TEST END -----"
	echo ""
}

main.sh

#! /bin/sh
# Define the _last_return value as "null"
__WITH_RETURNS=0
while [ $# -gt 0 ]; do
  case "$1" in
    --file*|-f*)
      if [[ "$1" != *=* ]]; then shift; fi
      FILE="${1#*=}"
      ;;
    --with-returns|-r)
      _last_return=
      __WITH_RETURNS=1
      ;;
    *)
      >&2 printf "Error: Invalid argument\n"
      exit 1
      ;;
  esac
  shift
done

source ./asserts.sh
source ./functions.sh
source ./files.sh

tests.sh

#! /bin/sh
#Building some functions based on bash scripts
#All functions that return something will write it's output to _last_return

source ./main.sh

#Start tests
start_test 'strlen test' 4
end_test

start_test 'str_replace test es acho' 'tachot'
end_test

start_test 'substr test 1' 'est'
end_test