Integration Testing
===================

## Installing Docker

Please refer to instructions at [https://github.com/druid-io/docker-druid/blob/master/docker-install.md](https://github.com/druid-io/docker-druid/blob/master/docker-install.md).

## Creating the Docker VM

Create a new VM for integration tests with at least 6GB of memory.

```
docker-machine create --driver virtualbox --virtualbox-memory 6000 integration
```

Set the docker environment:

```
eval "$(docker-machine env integration)"
export DOCKER_IP=$(docker-machine ip integration)
```

Running Integration tests
=========================

Make sure that you have at least 6GB of memory available before you run the tests.

## Starting docker tests

To run all the tests using docker and mvn run the following command -
```
  mvn verify -P integration-tests
```

To run only a single test using mvn run the following command -
```
  mvn verify -P integration-tests -Dit.test=<test_name>
```

## Configure and run integration tests using existing cluster

To run tests on any druid cluster that is already running, create a configuration file:

    {   
       "broker_host": "<broker_ip>",
       "broker_port": "<broker_port>",
       "router_host": "<router_ip>",
       "router_port": "<router_port>",
       "indexer_host": "<indexer_ip>",
       "indexer_port": "<indexer_port>",
       "coordinator_host": "<coordinator_ip>",
       "coordinator_port": "<coordinator_port>",
       "middle_manager_host": "<middle_manager_ip>",
       "zookeeper_hosts": "<comma-separated list of zookeeper_ip:zookeeper_port>",
    }

Set the environment variable CONFIG_FILE to the name of the configuration file -
```
export CONFIG_FILE=<config file name>
```

To run all the tests using mvn run the following command -
```
  mvn verify -P int-tests-config-file
```

To run only a single test using mvn run the following command -
```
  mvn verify -P int-tests-config-file -Dit.test=<test_name>
```

Writing a New Test
===============

## What should we cover in integration tests

For every end-user functionality provided by druid we should have an integration-test verifying the correctness.

## Rules to be followed while writing a new integration test

### Every Integration Test must follow these rules

1) Name of the test must start with a prefix "IT"
2) A test should be independent of other tests
3) Tests are to be written in TestNG style ([http://testng.org/doc/documentation-main.html#methods](http://testng.org/doc/documentation-main.html#methods))
4) If a test loads some data it is the responsibility of the test to clean up the data from the cluster

### How to use Guice Dependency Injection in a test

A test can access different helper and utility classes provided by test-framework in order to access Coordinator,Broker etc..
To mark a test be able to use Guice Dependency Injection -
Annotate the test class with the below annotation

```
 @Guice(moduleFactory = DruidTestModuleFactory.class)
```
This will tell the test framework that the test class needs to be constructed using guice.

### Helper Classes provided

1) IntegrationTestingConfig - configuration of the test
2) CoordinatorResourceTestClient - httpclient for coordinator endpoints
3) OverlordResourceTestClient - httpclient for indexer endpoints
4) QueryResourceTestClient - httpclient for broker endpoints

### Static Utility classes

1) RetryUtil - provides methods to retry an operation until it succeeds for configurable no. of times
2) FromFileTestQueryHelper - reads queries with expected results from file and executes them and verifies the results using ResultVerifier

Refer ITIndexerTest as an example on how to use dependency Injection

TODOS
=======================
1) Remove the patch for TestNG after resolution of Surefire-622