attempt to get associative array bugs to occur

test.sh

#!/bin/bash

set -o errexit
set -o nounset
set -o pipefail

source testlib.sh

testadd 'testkey' 'testval'

echo "${myarray['testkey']-}"

testlib.sh

#!/bin/bash

function testadd() {
	local key=$1
	shift
	local vals=$@

	for val in ${vals}; do
		testappend "${key}" "${val}"
	done
}

function testappend() {
	local key=$1
	local val=$2

	if ! echo "${myarray[${key}]-}" | grep -q "${val}"; then
		myarray["${key}"]="${myarray[${key}]-} ${val}"
	fi
}

if [[ -z "${myarray+x}" ]]; then
	declare -A myarray
fi