SudokuSolverTest.java

import org.junit.Test;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static org.junit.Assert.*;

public class SudokuSolverTest {

    private List<List<Integer>> expected;
    private boolean solved;
    private List<List<Integer>> partialAssignment;

    @Test
    public void solveSudoku1() throws Exception {
        expected = Arrays.asList(
                Arrays.asList(5,3,4,6,7,8,9,1,2),
                Arrays.asList(6,7,2,1,9,5,3,4,8),
                Arrays.asList(1,9,8,3,4,2,5,6,7),
                Arrays.asList(8,5,9,7,6,1,4,2,3),
                Arrays.asList(4,2,6,8,5,3,7,9,1),
                Arrays.asList(7,1,3,9,2,4,8,5,6),
                Arrays.asList(9,6,1,5,3,7,2,8,4),
                Arrays.asList(2,8,7,4,1,9,6,3,5),
                Arrays.asList(3,4,5,2,8,6,1,7,9)
        );
        solved = true;
        partialAssignment = Arrays.asList(
                Arrays.asList(5,3,0,0,7,0,0,0,0),
                Arrays.asList(6,0,0,1,9,5,0,0,0),
                Arrays.asList(0,9,8,0,0,0,0,6,0),
                Arrays.asList(8,0,0,0,6,0,0,0,3),
                Arrays.asList(4,0,0,8,0,3,0,0,1),
                Arrays.asList(7,0,0,0,2,0,0,0,6),
                Arrays.asList(0,6,0,0,0,0,2,8,0),
                Arrays.asList(0,0,0,4,1,9,0,0,5),
                Arrays.asList(0,0,0,0,8,0,0,7,9)
        );

        test(expected, solved, partialAssignment);
    }

    @Test
    public void solveSudoku2() throws Exception {
        expected = null;
        solved = false;
        partialAssignment = Arrays.asList(
                Arrays.asList(5,3,0,0,7,0,0,0,0),
                Arrays.asList(6,0,0,1,9,5,0,0,0),
                Arrays.asList(0,9,8,0,0,0,0,6,0),
                Arrays.asList(8,0,0,0,6,0,0,0,3),
                Arrays.asList(6,0,0,8,0,3,0,0,1),
                Arrays.asList(7,0,0,0,2,0,0,0,6),
                Arrays.asList(0,6,0,0,0,0,2,8,0),
                Arrays.asList(0,0,0,4,1,9,0,0,5),
                Arrays.asList(0,0,0,0,8,0,0,7,9)
        );

        test(expected, solved, partialAssignment);
    }

    private void test(List<List<Integer>> expected, boolean solved, List<List<Integer>> partialAssignment) {
        assertEquals(solved, SudokuSolver.solveSudoku(partialAssignment));
        if (solved)
            assertEquals(expected, partialAssignment);
    }

}