You need MySQL, PostgreSQL and Redis up and running.
MySQL should be accepting TCP connections on localhost:3306.
PostgreSQL should be accepting TCP connections on localhost:5432.
Redis should be accepting TCP connections on localhost:6379.
MySQL and PostgreSQL should grant full access to user 'ejabberd_test' with
password 'ejabberd_test' on database 'ejabberd_test'.

Here is a quick setup example:

------------------
  PostgreSQL
------------------
$ psql template1
template1=# CREATE USER ejabberd_test WITH PASSWORD 'ejabberd_test';
template1=# CREATE DATABASE ejabberd_test;
template1=# GRANT ALL PRIVILEGES ON DATABASE ejabberd_test TO ejabberd_test;
$ psql ejabberd_test -f sql/pg.sql

-------------------
  MySQL
-------------------
$ mysql
mysql> CREATE USER 'ejabberd_test'@'localhost' IDENTIFIED BY 'ejabberd_test';
mysql> CREATE DATABASE ejabberd_test;
mysql> GRANT ALL ON ejabberd_test.* TO 'ejabberd_test'@'localhost';
$ mysql ejabberd_test < sql/mysql.sql