You need MySQL, MSSQL, PostgreSQL and Redis up and running.
MySQL should be accepting TCP connections on localhost:3306.
MSSQL should be accepting TCP connections on localhost:1433.
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'.
MSSQL should grant full access to user 'ejabberd_test' with
password 'ejabberd_Test1' 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

-------------------
  MS SQL Server
-------------------
$ sqlcmd -U SA -P ejabberd_Test1 -S localhost
1> CREATE DATABASE ejabberd_test;
2> GO
1> USE ejabberd_test;
2> GO
Changed database context to 'ejabberd_test'.
1> CREATE LOGIN ejabberd_test WITH PASSWORD = 'ejabberd_Test1';
2> GO
1> CREATE USER ejabberd_test FOR LOGIN ejabberd_test;
2> GO
1> GRANT ALL TO ejabberd_test;
2> GO
The ALL permission is deprecated and maintained only for compatibility. It DOES NOT imply ALL permissions defined on the entity.
1> GRANT CONTROL ON SCHEMA ::dbo TO ejabberd_test;
2> GO
$ sqlcmd -U ejabberd_test -P ejabberd_Test1 -S localhost -d ejabberd_test -i sql/mssql.sql