Integration test

An integration test suite should be developed, so any Ecto adapters can be tested.

The test cases could be defined as JSON to make it easy for the community to contribute.

```json
[
{
"name": "test select statement",
"input”: ["select 1", {}],
"output": ["select 1", []],
"type”: "standard" // postgresql, tds, mysql …
}
…]
```