// put this line in your test's setUp() method
CascadingHelper.setTestMode();
// build your assembly
...
// use CascadingHelper's getFlowConnector instead of instantiating one directly
// and your tests will now run much faster!
CascadingHelper.get().getFlowConnector().connect(...).complete();

Pump.prime()
  .each(new RegexFilter("^[0-9]+"), "line")
  .each(new RegexSplitter(new Fields("timestamp", "tag"), ","), "line")
  .coerce(long.class, "timestamp")
  .each(new BucketizeTimestamp(), "bucketized_timestamp")
  .discard(timestamp)
  .rename("bucketized_timestamp", "timestamp");
  .groupby("timestamp", "tag");
  .every(new Count(new Fields("count")));