Partition { public Permutation toPermutation() { Permutation p = new Permutation(this.size()); for (int i = 0; i < this.size(); i++) { p.set(i, this.cells.get(i).first()); } return p; } Partition();  Partition(Partition other);  Partition(int[][] cellData); static Partition unit(int size); @Override boolean equals(Object o); @Override int hashCode(); int size(); int numberOfElements(); boolean isDiscrete(); Permutation toPermutation(); boolean inOrder(); int getFirstInCell(int cellIndex); SortedSet<Integer> getCell(int cellIndex); Partition splitBefore(int cellIndex, int splitElement); Partition splitAfter(int cellIndex, int splitElement); Permutation setAsPermutation(int upTo); boolean isDiscreteCell(int cellIndex); int getIndexOfFirstNonDiscreteCell(); void addSingletonCell(int element); void removeCell(int index); void addCell(int... elements); void addCell(Collection<Integer> elements); void addToCell(int index, int element); void insertCell(int index, SortedSet<Integer> cell); SortedSet<Integer> copyBlock(int cellIndex); void order(); boolean inSameCell(int elementI, int elementJ); @Override String toString(); static Partition fromString(String strForm);  }
@Test public void toPermutationTest() { int size = 5; Partition partition = new Partition(); for (int i = 0; i < size; i++) { partition.addSingletonCell(i); } Permutation permutation = partition.toPermutation(); Assert.assertEquals(size, permutation.size()); for (int i = 0; i < size; i++) { Assert.assertEquals(i, permutation.get(i)); } }