### Question:
UniqueColumnCombinationRanking extends Ranking { protected void calculateColumnRatio(UniqueColumnCombinationResult result) { Integer columnCount = result.getColumnCombination().getColumnIdentifiers().size(); Integer tableColumnCount = this.tableInformationMap.get(result.getTableName()).getColumnCount(); result.setColumnRatio((float) columnCount / tableColumnCount); } UniqueColumnCombinationRanking(List<UniqueColumnCombinationResult> results,
                                        Map<String, TableInformation> tableInformationMap); @Override void calculateDataIndependentRankings(); @Override void calculateDataDependentRankings();  }### Answer:
@Test public void testCalculateColumnRatio() throws Exception { UniqueColumnCombinationRanking ranking = new UniqueColumnCombinationRanking( uniqueColumnCombinationResults, tableInformationMap); UniqueColumnCombinationResult result = uniqueColumnCombinationResults.get(1); ranking.calculateColumnRatio(result); assertEquals(0.5, result.getColumnRatio(), 0.0); }