### Question:
ManyToManyMap { public int size() { return lToRMappings.size() + rToLMappings.size(); } ManyToManyMap();  ManyToManyMap(int initialCapacity);  ManyToManyMap(int initialCapacity, float loadFactor); void add(L left, R right); boolean remove(L left, R right); Set<R> removeAllMappingsForLeft(L left); Set<L> removeAllMappingsForRight(R right); Set<R> getRight(L left); Set<L> getLeft(R right); int size(); int numberOfmappingsForLeft(L left); int numberOfmappingsForRight(R right); boolean containsLeft(L left); boolean containsRight(R right); boolean isEmpty(); void clear(); Iterator<L> leftIterator(); Iterator<R> rightIterator(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testSize() { ManyToManyMap<String, String> map = new ManyToManyMap<String, String>(); assertEquals(0, map.size()); map.add("A.1", "A"); map.add("A.2", "A"); assertEquals(3, map.size()); }