### Question:
Int2FloatOpenHashMapWritable extends Int2FloatOpenHashMap implements Writable { public void increment(int key) { increment(key, 1.0f); } Int2FloatOpenHashMapWritable(); @Override void readFields(DataInput in); void decode(); boolean hasBeenDecoded(); @Override void write(DataOutput out); byte[] serialize(); static Int2FloatOpenHashMapWritable create(DataInput in); static Int2FloatOpenHashMapWritable create(byte[] bytes); void plus(Int2FloatOpenHashMapWritable m); int dot(Int2FloatOpenHashMapWritable m); void increment(int key); void increment(int key, float n); static void setLazyDecodeFlag(boolean b); static boolean getLazyDecodeFlag(); int[] getKeys(); float[] getValues(); void lazyplus(Int2FloatOpenHashMapWritable m); Int2FloatMap.Entry[] getEntriesSortedByValue(); Int2FloatMap.Entry[] getEntriesSortedByValue(int k);  }### Answer:
@Test public void testIncrement() throws IOException { Int2FloatOpenHashMapWritable m = new Int2FloatOpenHashMapWritable(); m.put(2, 7.0f); m.put(1, 29.0f); assertEquals(7, m.get(2), 10e-6); assertEquals(29, m.get(1), 10e-6); m.increment(2); m.increment(1); m.increment(3); assertEquals(8, m.get(2), 10e-6); assertEquals(30, m.get(1), 10e-6); assertEquals(1, m.get(3), 10e-6); m.increment(1, 3.0f); m.increment(3, 5.0f); assertEquals(8, m.get(2), 10e-6); assertEquals(33, m.get(1), 10e-6); assertEquals(6, m.get(3), 10e-6); }