@AfterClass
  public static void tearDown() throws Exception {
    Closeables.close(TABLE, true);
    Closeables.close(CONN, true);
    UTIL.shutdownMiniCluster();
  }
These tests verify that the RPC timeouts ('hbase.client.operation.timeout' and
'hbase.client.scanner.timeout.period') work correctly using a modified Region Server which
injects delays to get, scan and mutate operations.
<p/>
When 'hbase.client.operation.timeout' is set and client operation is not completed in time the
client will retry the operation 'hbase.client.retries.number' times. After that
{@link SocketTimeoutException} will be thrown.
<p/>
Using 'hbase.client.scanner.timeout.period' configuration property similar behavior can be
specified for scan related operations such as openScanner(), next(). If that times out
{@link RetriesExhaustedException} will be thrown.
hbase-server/src/test/java/org/apache/hadoop/hbase/TestClientOperationTimeout.java