@Test(expected = IOException.class)
public final void testMapperForNullKeyValue() throws IOException,
InterruptedException {
Mapper.Context context = mock(Mapper.Context.class);
Counters counters = new Counters();
Counter counter = counters.findCounter(MergeRecordCounter.BAD_RECORD);
when(context.getCounter(MergeRecordCounter.BAD_RECORD)).thenReturn(
counter);
MergeKeyMapper mapper = new MergeKeyMapper();
Text val = new Text("valueOfKey");
mapper.map(null, val, context);