Apache Accumulo Documentation : Mock Accumulo

Normally, accumulo consists of lots of moving parts. Even a stand-alone version of accumulo requires hadoop, zookeeper, the accumulo master, a tablet server, etc. If you want to write a unit test that uses accumulo, you need a lot of infrastructure in place before your test can run. To help developers with their tests, we have created a fake version of Accumulo called MockAccumulo. The normal interaction with the client API looks something like this:

   Instance instance = new ZooKeeperInstance(...);
   Connector conn = instance.getConnector(user, passwd);
   BatchScanner scanner = conn.createBatchScaner(...);
   // configure scanner
   // ...
   for (Entry entry : scanner) {
       // process entry
   }

MockAccumulo supports the same client API. Just replace the ZooKeeperInstance with MockInstance:

   Instance instance = new MockInstance();
   // as above

In fact, you can use the --fake option to the accumulo shell and interact with MockAccumulo:

$ ./bin/accumulo shell --fake -u root -p nonsense

Shell - Apache Accumulo Interactive Shell
- 
- version: 1.3.6
- instance name: mock-instance
- instance id: mock-instance-id
- 
- type 'help' for a list of available commands
- 
root@mock-instance> createtable test
root@mock-instance test> insert row1 cf cq value
root@mock-instance test> insert row2 cf cq value2
root@mock-instance test> insert row3 cf cq value3
root@mock-instance test> scan
row1 cf:cq []    value
row2 cf:cq []    value2
row3 cf:cq []    value3
root@mock-instance test> scan -b row2 -e row2
row2 cf:cq []    value2
root@mock-instance test> 

MockAccumulo presently does not enforce users, logins, permissions, etc. It does support Iterators and Aggregators. Note that MockAccumulo holds all data in memory, and will not retain any data or settings between runs.