protected void runLoadTestOnExistingTable() throws IOException {
    writerThreads.start(0, numKeys, NUM_THREADS);
    writerThreads.waitForFinish();
    assertEquals(0, writerThreads.getNumWriteFailures());

    readerThreads.start(0, numKeys, NUM_THREADS);
    readerThreads.waitForFinish();
    assertEquals(0, readerThreads.getNumReadFailures());
    assertEquals(0, readerThreads.getNumReadErrors());
    assertEquals(numKeys, readerThreads.getNumKeysVerified());
  }
A write/read/verify load test on a mini HBase cluster. Tests reading and then writing.
hbase-diagnostics/src/test/java/org/apache/hadoop/hbase/util/TestMiniClusterLoadSequential.java