### Question:
SuperSetGraph { public boolean isEmpty() { return this.graph.isEmpty(); } SuperSetGraph(int numberOfColumns); SuperSetGraph add(ColumnCombinationBitset columnCombination); SuperSetGraph addAll(Collection<ColumnCombinationBitset> columnCombinations); ArrayList<ColumnCombinationBitset> getExistingSupersets(ColumnCombinationBitset subset); boolean containsSuperset(ColumnCombinationBitset subset); boolean isEmpty(); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void testIsEmpty() { SuperSetGraph emptyGraph = new SuperSetGraph(fixture.getNumberOfColumns()); SuperSetGraph nonEmptyGraph = new SuperSetGraph(fixture.getNumberOfColumns()); nonEmptyGraph.add(new ColumnCombinationBitset(10)); assertTrue(emptyGraph.isEmpty()); assertFalse(nonEmptyGraph.isEmpty()); }