Test with Solr

[at15]

Since it is a solr client, it should test against real solr (w/ & w/o SolrCloud)

• sendgrid uses docker compose on travis https://github.com/sendgrid/go-solr
• go-solr uses mock https://github.com/vanng822/go-solr/blob/master/solr/solr_test.go
• shippable has built in docker compose support http://docs.shippable.com/ci/docker-compose/

We can also use docker-compose to run test locally, though it is more convenient to use a local Solr

• docker-compose setup (single node, no zk)
• code coverage
• unit test helpers (create core etc.) [test] Use external script to setup test environment #7
• e2e tests