private static void initSrcTablesFromSystemProperty() {
    srcTables = new HashSet<String>();
    // FIXME: moved default value to here...for now
    // i think this features is never really used from the command line
    for (String srcTable : QTestSystemProperties.getSrcTables()) {
      srcTable = srcTable.trim();
      if (!srcTable.isEmpty()) {
        srcTables.add(srcTable);
      }
    }
  }
Datasets are provided by this handler.

An invocation of:

<pre>
--! qt:dataset:sample
--! qt:dataset:sample:ONLY
</pre>

will make sure that the dataset named sample is loaded prior to executing the test.
itests/util/src/main/java/org/apache/hadoop/hive/ql/dataset/QTestDatasetHandler.java