### Question:
Poset implements Serializable { public T getGLB(Set<T> subset) { return getUniqueBound(subset, lowerBound); }  static Poset<T> create(); java.util.Set<T> getElements(); void addElement(T element); void add(Poset<T> poset); void addRelation(T big, T small); boolean isInRelation(T big, T small); void transitiveClosure(); T getMaxim(T start); T getLUB(Set<T> subset); T getGLB(Set<T> subset); Set<T> getMaximalLowerBounds(Set<T> subset); Set<T> getMinimalUpperBounds(Set<T> subset); List<T> checkForCycles();  }### Answer:
@Test public void testGetGLB() throws Exception { Assert.assertNull(poset.getGLB(Sets.newHashSet("A0", "A1", "A2"))); poset.addRelation("A0", "GLB"); poset.addRelation("A1", "GLB"); poset.addRelation("A2", "GLB"); poset.addRelation("GLB", "B0"); poset.addRelation("GLB", "B1"); poset.transitiveClosure(); Assert.assertEquals("GLB", poset.getGLB(Sets.newHashSet("A0", "A1", "A2"))); }