@BeforeClass
  public static void beforeClass() throws Exception {
    // Set my test Coprocessors into the Configuration before we start up the cluster.
    Configuration conf = HTU.getConfiguration();
    conf.setStrings(CoprocessorHost.MASTER_COPROCESSOR_CONF_KEY,
      TestMasterCoprocessor.class.getName());
    conf.setStrings(CoprocessorHost.REGIONSERVER_COPROCESSOR_CONF_KEY,
      TestRegionServerCoprocessor.class.getName());
    conf.setStrings(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY,
      TestRegionCoprocessor.class.getName());
    HTU.startMiniCluster();
  }
Start up a mini cluster with my three CPs loaded.
hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorSharedConnection.java