bash-tests

#!/bin/bash

# bash-tests - bash library for unit and integration tests
#
# Copyright (C) 2019  Christian Garbs <mitch@cgarbs.de>
# Licensed under GNU GPL v3 or later.
#
# This file is part of bash-n.
#
# bash-n is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# bash-n is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with bash-n.  If not, see <http://www.gnu.org/licenses/>.

set -e

############################
#
# public test interface
#

# perform an assertion
# $1 SUBJECT to check
# $* PARAMETERS depending on SUBJECT
assert_that()
{
    local subject=$1
    shift

    case $subject in
	variable)
	    _assert_variable "${@}"
	    ;;
	stdout)
	    _assert_stdout "${@}"
	    ;;
	*)
	    fail "unknown test subject <$subject> in assert_that"
	    ;;
    esac
}

# fail the test with a message
# $* MESSAGE
fail()
{
    echo "${term_error}$*${term_normal}" >&2
    exit 1
}

############################
#
# private methods
#

_add_empty_before_test_if_missing()
{
    if ! declare -F before_test; then
	before_test()
	{
	    :
	}
    fi
}

_setup_colors()
{
    if tput sgr0 >/dev/null 2>&1; then
	term_normal=$(tput sgr0)
	term_error=$(tput setaf 1)
	term_success=$(tput setaf 2)
    else
	term_normal=
	term_error=
	term_success=
    fi

    echo -n $term_normal
}

_setup_test_name()
{
    test_script=${BASH_SOURCE[${#BASH_SOURCE[@]} - 1]}
    test_script=${test_script##/*}
    test_script=${test_script:-unknown}
}

_create_tmpdir()
{
    tmpdir=$(mktemp -d)
    trap "rm -rf '$tmpdir'" EXIT
}

_scan_test_methods()
{
    test_method_file=$tmpdir/tests
    declare -F | sed 's/^declare -f //' | grep ^test_ | sort -R > $test_method_file
    read -r test_count _ <<< $(wc -l "$test_method_file")
    if [ "$test_count" -lt 1 ]; then
	fail "no tests defined"
    fi
}

# $1 ACTUAL value
# $2 EXPECTED value
_assert_equals()
{
    local actual=$1 expected=$2

    if [ "$actual" != "$expected" ]; then
	fail "expected <$expected> but got <$actual>"
    fi
}

# $1 VARIABLE to check
# $2 VERB describing the check
# $* PARAMETERS depending on VERB
_assert_variable()
{
    local variable=$1 verb=$2 expected=$3

    echo -n "    check \$$variable: " >&2

    case $verb in
	is)
	    _assert_equals "${!variable}" "$expected"
	    ;;
	*)
	    fail "unknown verb <$verb> in <assert_that variable>"
	    ;;
    esac

    echo "ok" >&2
}

# $1 VERB describing the check
_assert_stdout()
{
    local verb=$1

    echo -n "    check stdout: " >&2

    [ "$verb" != 'is' ] && fail "unknown verb <$verb> in <assert_that stdout>"

    export tmpdir
    (
	cd "$tmpdir"
	cat > expected
	cp stdout actual

	if ! cmp -s expected actual; then
	    diff -Narup expected actual >&2
	    fail "!! output differs"
	fi
    ) || exit 1

    echo "ok" >&2
}

# $1 TEST NAME is the declared bash function to call
_run_test()
{
    local test_stdout=$tmpdir/stdout

    echo "  $test_name" >&2
    before_test
    $test_name > "$test_stdout" || fail "execution failed"
    test_ok_count=$((test_ok_count + 1))
}

############################
#
# test execution
#

_setup_test_name
_setup_colors
_create_tmpdir
_scan_test_methods
_add_empty_before_test_if_missing

test_ok_count=0

while IFS= read -u 9 -r test_name; do
    _run_test "$test_name"
done 9<"$test_method_file" 

if [ $test_count == $test_ok_count ]; then
    tests_missing=false
    echo -n $term_success >&2
else
    tests_missing=true
    echo -n $term_error >&2
fi

printf "%s: %d/%d tests ok%s\n" $test_script $test_ok_count $test_count $term_normal >&2

if $tests_missing; then
    fail "some test executions are missing!"
fi

exit 0