@Test
  public void testDeleteFamily() throws Exception {
    createTable(TestDeleteFamilyCoprocessor.class.getName());

    try (Table t = util.getConnection().getTable(tableName)) {
      t.put(Lists.newArrayList(new Put(row1).addColumn(test, dummy, dummy),
        new Put(row2).addColumn(test, dummy, dummy), new Put(row3).addColumn(test, dummy, dummy)));

      assertRowCount(t, 3);

      t.delete(new Delete(test).addFamily(test)); // delete non-existing row
      assertRowCount(t, 1);
    }
  }
Tests that added mutations from coprocessors end up in the WAL.
hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverForAddingMutationsFromCoprocessors.java