### Question:
ColumnCombinationBitset implements Comparable<ColumnCombinationBitset> { @Override public int compareTo(ColumnCombinationBitset other) { long sizeComparator = this.bitset.cardinality() - other.bitset.cardinality(); if (sizeComparator != 0) { return (int) sizeComparator; } Iterator<Integer> iterator = this.getSetBits().iterator(); Iterator<Integer> iterator2 = other.getSetBits().iterator(); while (iterator.hasNext()) { int thisBit = iterator.next().intValue(); int otherBit = iterator2.next().intValue(); int bitComparator = thisBit - otherBit; if (bitComparator != 0) { return bitComparator; } } return 0; } 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 testCompareTo() { ColumnCombinationBitset set1 = new ColumnCombinationBitset().addColumn(2); ColumnCombinationBitset set2 = new ColumnCombinationBitset().addColumn(1); ColumnCombinationBitset set3 = new ColumnCombinationBitset().addColumn(1).addColumn(3); ColumnCombinationBitset set4 = new ColumnCombinationBitset().addColumn(2); ColumnCombinationBitset set5 = new ColumnCombinationBitset().addColumn(1).addColumn(3); CompareToTester<ColumnCombinationBitset> testerSet1 = new CompareToTester<>(set1); CompareToTester<ColumnCombinationBitset> testerSet2 = new CompareToTester<>(set2); CompareToTester<ColumnCombinationBitset> testerSet3 = new CompareToTester<>(set3); testerSet1.performCompareToTestEqual(set1, set4); testerSet1.performCompareToTestGreater(set3); testerSet1.performCompareToTestSmaller(set2); testerSet2.performCompareToTestGreater(set3, set4); testerSet3.performCompareToTestEqual(set5); }