### Question:
ColumnCombinationBitset implements Comparable<ColumnCombinationBitset> { public boolean isSubsetOf(ColumnCombinationBitset potentialSuperset) { return potentialSuperset.containsSubset(this); } ColumnCombinationBitset(int... columnIndeces);  ColumnCombinationBitset(List<Integer> columnIndices);  ColumnCombinationBitset(ColumnCombinationBitset columnCombination); ColumnCombinationBitset addColumn(int columnIndex); ColumnCombinationBitset removeColumn(int columnIndex); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString(); boolean isSubsetOf(ColumnCombinationBitset potentialSuperset); boolean isProperSubsetOf(ColumnCombinationBitset potentialProperSuperSet); boolean containsSubset(ColumnCombinationBitset potentialSubset); boolean containsProperSubset(ColumnCombinationBitset potentialProperSubset); List<ColumnCombinationBitset> getAllSubsets(); List<ColumnCombinationBitset> getNSubsetColumnCombinations(int n); List<ColumnCombinationBitset> getNSubsetColumnCombinationsSupersetOf(
    ColumnCombinationBitset subSet, int n); List<Integer> getSetBits(); List<Integer> getClearedBits(int numberOfColumns); ColumnCombinationBitset minus(
    ColumnCombinationBitset otherColumnCombination); List<ColumnCombinationBitset> getContainedOneColumnCombinations(); ColumnCombinationBitset union(ColumnCombinationBitset other); ColumnCombinationBitset intersect(ColumnCombinationBitset other); List<ColumnCombinationBitset> getDirectSupersets(int numberOfColumns); List<ColumnCombinationBitset> getDirectSupersets(ColumnCombinationBitset maximalSuperset); List<ColumnCombinationBitset> getDirectSubsets(); List<ColumnCombinationBitset> getDirectSubsetsSupersetOf(ColumnCombinationBitset subSet); int size(); boolean isEmpty(); ColumnCombination createColumnCombination(String relationName,
                                                   List<String> columnNames); ColumnCombinationBitset setAllBits(int dimension); boolean containsColumn(int columnIndex); boolean containsColumn(int... columnIndices); ColumnCombinationBitset invert(int size); @Override int compareTo(ColumnCombinationBitset other);  }### Answer:
@Test public void testIsSubsetOf() { ColumnCombinationBitset subSet = new ColumnCombinationBitset(0, 3); ColumnCombinationBitset superSet = new ColumnCombinationBitset(0, 2, 3); assertTrue(subSet.isSubsetOf(superSet)); assertTrue(subSet.isSubsetOf(subSet)); assertFalse(superSet.isSubsetOf(subSet)); }