tests.username and tests.password need to be configured in your ~/.m2/settings.xml like this:

<?xml version="1.0" encoding="UTF-8"?>
<settings>
...
   <profiles>
        <profile>
            <id>amenlib-properties</id>
            <properties>
                <tests.username>email@some.domain</tests.username>
                <tests.password>mypass</tests.password>
            </properties>
        </profile>
   </profiles>
...
   <activeProfiles>
        <activeProfile>amenlib-properties</activeProfile>
   </activeProfiles>
</setting>