RecordReader<LongWritable, Text> reader = input.getRecordReader(split, job, reporter);
LongWritable key = reader.createKey();
Text value = reader.createValue();
Step0Mapper mapper = new Step0Mapper();
mapper.configure(p);
Long firstKey = null;
int size = 0;
while (reader.next(key, value)) {
if (firstKey == null) {
firstKey = key.get();
}
mapper.map(key, value, collector, reporter);
size++;
}
mapper.close();
// validate the mapper's output
assertEquals(p, collector.keys[p]);
assertEquals(firstKey.longValue(), collector.values[p].getFirstId());
assertEquals(size, collector.values[p].getSize());