Travis OS X test Postgres - macos

Question

How can I set Postgres in Travis CI OS X build?
I can't start and I don't know how to set these:
--dbaddress localhost --dbport 5432 --dbname testDb --dbusername postgres

Answer 1

With the Travis CI OS X instances the environment is similar to a typical Homebrew installation.
Here is the Travis CI OS X environment you can configure.
The database services that are available:
postgis version 2.1.3, postgresql version 9.3.5
Unlike Linux, the service configuration is not currently available in OSX. You start a database service using the install script and making use of the Postgresql tools directly.
An example .travis.yml looks like this:
addons:
postgresql: "9.4"
language:
- objective-c
os:
- osx
sudo:
- false
install:
- export PG_DATA=$(brew --prefix)/var/postgres
- pg_ctl -w start -l postgres.log --pgdata ${PG_DATA}
- createuser -s postgres
- psql -c 'create database testDb;' -U postgres
- cat postgres.log
So what does it do?
“add ons” is selecting your specific postgresql version over the default
“sudo” commands cannot be executed in Travis CI
“install” contains the commands we need to run and others you want to add
The pg_ctl command requires a data directory, “PG_DATA” contains a path to the local home-brew installation and your directory to store database files.
pg_ctl will start the existing service and wait(-w) to be connected.
A unix user/role "postgres" must be created and is used in the final creation script for your database “testDb”.
Finally, the postgres.log is sent to Travis CI log.
Hopefully, that gives you an idea of where to start.

Answer 2

Additional information to griffio's answer:
In the meantime Travis is running PostgreSQL 9.5 (even with addon postgresql: "9.4") and I got the following log output when starting:
FATAL: database files are incompatible with server
DETAIL: The data directory was initialized by PostgreSQL version 9.4, which is not compatible with this version 9.5.4.
It's working after creating a new cluster first:
install:
- export PG_DATA=$(brew --prefix)/var/postgres
- rm -rf $PG_DATA
- initdb $PG_DATA -E utf8
- pg_ctl -w start -l postgres.log --pgdata ${PG_DATA}
- createuser -s postgres
- psql -c 'create database testDb;' -U postgres