Merge branch 'solver'

# Conflicts:
#	app/src/main/java/sudoku/Main.java
#	app/src/main/java/sudoku/Sudoku.java

app/src/main/java/sudoku/Block.java

@@ -31,4 +31,12 @@ public class Block {
 		return false;
 	}
 
+	public boolean containsCell(Cell cell) {
+		for (Cell cellTmp : this.cells) {
+			if (cellTmp.equals(cell)) {
+				return true;
+			}
+		}
+		return false;
+	}
 }

app/src/main/java/sudoku/Cell.java

@@ -1,94 +1,74 @@
 package sudoku;
 
-import org.checkerframework.checker.units.qual.C;
-
 import java.util.ArrayList;
 import java.util.List;
 
-public abstract class Cell {
+public class Cell {
 
-	protected static int NOSYMBOL = -1;
+	public static int NOSYMBOL = -1;
-	protected int symbolIndex;
+
-	protected Block block = null;
+	private Block blockContainer;
-	//protected List<Block> blockContainers = null;
+	private int symbolIndex = Cell.NOSYMBOL;
-	//protected List<Sudoku> sudokuContainers = null;
+	private final List<Integer> possibleSymbols;
+	private boolean isMutable = true;
+
+	public Cell() {
+		this.possibleSymbols = new ArrayList<>();
+	}
 
 	public Cell(int symbolIndex) {
 		this.symbolIndex = symbolIndex;
+		this.possibleSymbols = new ArrayList<>();
 	}
 
-	/**
-	 * @brief Default constructor, empty square
-	 */
-	public Cell() {
-		this(NOSYMBOL);
-	}
-
-	/*
-
-	public Cell(Cell cell) {
-		this.symbolIndex = cell.symbolIndex;
-		this.sudokuContainers = cell.sudokuContainers;
-		this.blockContainers  = cell.blockContainers;
-	}
-
-	public Cell(List<Sudoku> sudokuContainers, List<Block> blockContainers) {
-		super();
-		this.sudokuContainers = new ArrayList<>(sudokuContainers);
-		this.blockContainers  = new ArrayList<>(blockContainers);
-	}
-
-	 */
-
 	public int getSymbolIndex() {
-		return symbolIndex;
+		return this.symbolIndex;
+	}
+
+	public void setSymbolIndex(int symbolIndex) {
+		this.symbolIndex = symbolIndex;
+	}
+
+	public void setPossibleSymbols(List<Integer> possibleSymbols) {
+		this.possibleSymbols.clear();
+		this.possibleSymbols.addAll(possibleSymbols);
+	}
+
+	public void setImmutable() {
+		this.isMutable = false;
 	}
 
 	public Block getBlock() {
-		return this.block;
+		return this.blockContainer;
 	}
 
-	/*
-	public List<Block> getBlockContainers() {
-		return this.blockContainers;
-	}
-
-	public void setBlockContainers(List<Block> block) {
-		this.blockContainers = block;
-	}
-
-	public List<Sudoku> getSudokuContainers() {
-		return this.sudokuContainers;
-	}
-*/
-	// only SudokuFactory and SudokuSerializer should access this
 	public void setBlock(Block block) {
-		this.block = block;
+		this.blockContainer = block;
 	}
 
-	/*
+	/**
-	public void setSudokuContainers(List<Sudoku> sudoku) {
+	 * Remove the current symbolIndex and returns it
-		this.sudokuContainers = sudoku;
+	 * @return integer symbolIndex cleared
-	}
+	 */
-	*/
+	public int clearCurrentSymbol() {
-
+		int i = this.symbolIndex;
-	public boolean equalsValue(Cell otherCell) {
+		setSymbolIndex(NOSYMBOL);
-		return otherCell.getSymbolIndex() == this.getSymbolIndex();
+		return i;
 	}
 
-	@Override
+	public boolean isEmpty() {
-	public String toString() {
+		return this.symbolIndex == Cell.NOSYMBOL;
-		StringBuilder sb = new StringBuilder();
-		sb.append("| ");
-		if (this.symbolIndex != NOSYMBOL){
-			sb.append(this.symbolIndex);
-		}
-		else {
-			sb.append(" ");
-		}
-
-		sb.append(" |");
-		return sb.toString();
 	}
 
+	public void removeSymbolFromPossibilities(int indexSymbol) {
+		possibleSymbols.remove(indexSymbol);
+	}
+
+	public List<Integer> getPossibleSymbols() {
+		return this.possibleSymbols;
+	}
+
+	public boolean isMutable() {
+		return this.isMutable;
+	}
 }

app/src/main/java/sudoku/Coordinate.java

@@ -5,9 +5,9 @@ public class Coordinate {
     private int x;
     private int y;
 
-    public Coordinate(int row, int col) {
+    public Coordinate(int x, int y) {
-        this.x = row;
+        this.x = x;
-        this.y = col;
+        this.y = y;
     }
 
     public int getX() {

app/src/main/java/sudoku/Main.java

@@ -3,10 +3,10 @@
  */
 package sudoku;
 
-import java.util.Arrays;
-
 import sudoku.io.SudokuPrinter;
 
+import java.util.Arrays;
+
 public class Main {
     public String getGreeting() {
         return "Hello World!";

app/src/main/java/sudoku/MultiDoku.java

@@ -1,7 +1,5 @@
 package sudoku;
 
-import sudoku.constraint.IConstraint;
-
 import java.util.ArrayList;
 import java.util.List;
 
@@ -26,12 +24,12 @@ public class MultiDoku {
 		return subGrids.get(i);
 	}
 
-	public List<MutableCell> getMutableCells(){
+	public List<Cell> getCells(){
-		List<MutableCell> mutableCells = new ArrayList<>();
+		List<Cell> cells = new ArrayList<>();
 		for (Sudoku sudoku : subGrids){
-			mutableCells.addAll(sudoku.getMutableCells());
+			cells.addAll(sudoku.getCells());
 		}
-		return mutableCells;
+		return cells;
 	}
 
 	public void updateSymbolsPossibilities() throws Exception {
@@ -50,4 +48,55 @@ public class MultiDoku {
 		sb.append("\n}");
 		return sb.toString();
 	}
+
+	public Cell getFirstEmptyCell() {
+		for (Sudoku sudoku : this.subGrids) {
+			Cell cellTmp = sudoku.getFirstEmptyCell();
+			if (cellTmp != null && cellTmp.isEmpty()) {
+				return cellTmp;
+			}
+		}
+		return null;
+	}
+
+	public List<Integer> getPossibleSymbolsOfCell(Cell cellToFill) {
+		for (Sudoku sudoku : this.subGrids) {
+			if (sudoku.contains(cellToFill)) {
+				return sudoku.getPossibleSymbolsOfCell(cellToFill);
+			}
+		}
+		return new ArrayList<>();
+	}
+
+	public List<Sudoku> getSubGrids() {
+		return this.subGrids;
+	}
+
+	public boolean isValid() {
+		boolean result = true;
+		for (Sudoku sudoku : this.subGrids) {
+			result = sudoku.isValid() && result;
+		}
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object object) {
+		if (!(object instanceof MultiDoku)) {
+			return false;
+		}
+
+		if (this.getNbSubGrids() != ((MultiDoku) object).getNbSubGrids()) {
+			return false;
+		}
+
+		for (int i = 0; i < this.getNbSubGrids(); i++) {
+			if (!this.getSubGrid(i).equals(((MultiDoku) object).getSubGrid(i))) {
+				return false;
+			}
+		}
+
+		return true;
+	}
 }
+

app/src/main/java/sudoku/MutableCell.java

@@ -1,47 +0,0 @@
-package sudoku;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class MutableCell extends Cell{
-
-	private final List<Integer> possibleSymbols;
-
-	public MutableCell() {
-		super();
-		this.possibleSymbols = new ArrayList<>();
-	}
-
-	public MutableCell(int symbolIndex) {
-		super(symbolIndex);
-		this.possibleSymbols = new ArrayList<>();
-	}
-
-	public void setSymbolIndex(int symbolIndex) {
-		this.symbolIndex = symbolIndex;
-	}
-
-	public void setPossibleSymbols(List<Integer> possibleSymbols) {
-		this.possibleSymbols.clear();
-		this.possibleSymbols.addAll(possibleSymbols);
-	}
-
-	/**
-	 * Remove the current symbolIndex and returns it
-	 * @return integer symbolIndex cleared
-	 */
-	public int clearCurrentSymbol() {
-		int i = this.symbolIndex;
-		setSymbolIndex(NOSYMBOL);
-		return i;
-	}
-
-	public void removeSymbolFromPossibilities(int indexSymbol) {
-		possibleSymbols.remove(indexSymbol);
-	}
-
-	public List<Integer> getPossibleSymbols() {
-		return this.possibleSymbols;
-	}
-
-}

app/src/main/java/sudoku/Sudoku.java

@@ -14,6 +14,7 @@ public class Sudoku {
 	private final List<Block> blocks;
 	private final List<Cell> cells;
 	private final List<IConstraint> constraints;
+	private boolean isMutable;
 
 	public Sudoku(List<Cell> cells, List<Block> blocks, List<IConstraint> constraints) {
 		this.cells = cells;
@@ -32,21 +33,18 @@ public class Sudoku {
 	/**
 	 * Try to place a cell at the given coordinate
 	 *
-	 * @return false if it can't be done
+	 * @return Cell created or null if it can't be done
 	 */
-	public boolean setCellSymbol(int x, int y, int value) {
+	public Cell setCellSymbol(int x, int y, int value) {
 		assert (isValidCoords(x, y));
 		for (IConstraint constraint : this.constraints) {
 			if (!constraint.canBePlaced(this, x, y, value)) {
-				return false;
+				return null;
 			}
 		}
 		Cell cell = getCell(x, y);
-		if (cell instanceof MutableCell mCell) {
+		cell.setSymbolIndex(value);
-			mCell.setSymbolIndex(value);
+		return cell;
-			return true;
-		}
-		return false;
 	}
 
 	public boolean setCellsSymbol(List<Integer> values) {
@@ -55,19 +53,41 @@ public class Sudoku {
 		}
 		for (int i = 0; i < values.size(); i++) {
 			int x = i % this.blocks.size();
-			int y = (i - x) / this.blocks.size();
+			int y = (i-x) / this.blocks.size();
 			int value = values.get(i);
-			if (!this.setCellSymbol(x, y, value)) {
+			this.setCellSymbol(x, y, value);
-				return false;
+		}
+		return true;
+	}
+
+	public boolean setImmutableCellsSymbol(List<Integer> values) {
+		if (values.size() > this.cells.size()) {
+			return false;
+		}
+		for (int i = 0; i < values.size(); i++) {
+			int x = i%this.blocks.size();
+			int y = (i-x)/this.blocks.size();
+			int value = values.get(i);
+			if (value != Cell.NOSYMBOL) {
+				Cell cellPlaced = this.setCellSymbol(x, y, value);
+				if (cellPlaced == null) {
+					continue;
+				}
+				cellPlaced.setImmutable();
 			}
 		}
 		return true;
 	}
 
+
 	public Cell getCell(int x, int y) {
 		int index = y * getSize() + x;
 		assert (isValidCoords(x, y));
-		return this.cells.get(index);
+		try {
+            return this.cells.get(index);
+		} catch (IndexOutOfBoundsException e) {
+			return null;
+		}
 	}
 
 	public Cell getCell(int i) {
@@ -82,12 +102,6 @@ public class Sudoku {
 		return this.blocks.size();
 	}
 
-	public boolean isValid(List<IConstraint> constraints) {
-		// not implemented
-		// for eachcase check contraintes
-		return false;
-	}
-
 	public List<Cell> getCells() {
 		return this.cells;
 	}
@@ -96,16 +110,6 @@ public class Sudoku {
 		return this.blocks;
 	}
 
-	public List<MutableCell> getMutableCells() {
-		List<MutableCell> mutableCells = new ArrayList<>();
-		for (Cell cell : this.cells) {
-			if (cell instanceof MutableCell) {
-				mutableCells.add((MutableCell) cell);
-			}
-		}
-		return mutableCells;
-	}
-
 	public boolean contains(Cell cell) {
 		return this.cells.contains(cell);
 	}
@@ -134,8 +138,8 @@ public class Sudoku {
 
 	public void updateSymbolsPossibilities() throws Exception {
 		for (IConstraint constraint : constraints) {
-			List<MutableCell> mutableCells = this.getMutableCells();
+			List<Cell> cells = this.getCells();
-			for (MutableCell cell : mutableCells) {
+			for (Cell cell : cells) {
 				Coordinate coord = null;
 				try {
 					coord = this.getCoordinateCell(cell);
@@ -154,7 +158,6 @@ public class Sudoku {
 		}
 	}
 
-	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
 		sb.append("Sudoku {");
@@ -168,4 +171,78 @@ public class Sudoku {
 		sb.append("\n}");
 		return sb.toString();
 	}
+
+	public Cell getFirstEmptyCell() {
+		for (Cell cell : this.cells) {
+			if (cell.isEmpty()) {
+				return cell;
+			}
+		}
+		return null;
+	}
+
+	public List<Integer> getPossibleSymbolsOfCell(Cell cellToFill) {
+		List<Integer> result = new ArrayList<>();
+		Coordinate cellCoordinates;
+		try {
+			cellCoordinates = this.getCoordinateCell(cellToFill);
+		} catch (Exception e) {
+			return result;
+		}
+		for (IConstraint constraint : this.constraints) {
+			if (result.isEmpty()) {
+				result.addAll(constraint.getPossibleSymbols(this, cellCoordinates.getX(), cellCoordinates.getY()));
+			} else {
+				result.retainAll(constraint.getPossibleSymbols(this, cellCoordinates.getX(), cellCoordinates.getY()));
+			}
+		}
+		return result;
+	}
+
+	public boolean isValid() {
+		for (Cell cell : this.cells) {
+			if (cell.isMutable()) {
+				if (cell.isEmpty()) {
+					return false;
+				}
+				for (IConstraint constraint : this.constraints) {
+					Coordinate coords;
+					try {
+						int symbolPlaced = cell.getSymbolIndex();
+						coords = this.getCoordinateCell(cell);
+
+						cell.setSymbolIndex(Cell.NOSYMBOL);
+						List<Integer> possibleSymbols = constraint.getPossibleSymbols(this, coords.getX(), coords.getY());
+						cell.setSymbolIndex(symbolPlaced);
+						if (possibleSymbols.size() != 1 || possibleSymbols.get(0) != symbolPlaced) {
+							return false;
+						}
+
+					} catch (Exception e) {
+						throw new RuntimeException(e);
+					}
+				}
+			}
+		}
+		return true;
+	}
+
+	@Override
+	public boolean equals(Object object) {
+		if (!(object instanceof Sudoku)) {
+			return false;
+		}
+
+		if (this.getSize() != ((Sudoku) object).getSize()) {
+			return false;
+		}
+
+		for (int i = 0; i < this.getSize(); i++) {
+			if (this.getCell(i).getSymbolIndex() != ((Sudoku) object).getCell(i).getSymbolIndex()) {
+				return false;
+			}
+		}
+
+		return true;
+	}
 }

app/src/main/java/sudoku/SudokuFactory.java

@@ -7,13 +7,14 @@ import sudoku.constraint.LineConstraint;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 public class SudokuFactory {
 
 	private static List<Cell> initCells(int size) {
 		List<Cell> cells = new ArrayList<>(size * size);
 		for (int i = 0; i < size * size; i++) {
-			cells.add(new MutableCell());
+			cells.add(new Cell());
 		}
 		return cells;
 	}
@@ -59,4 +60,15 @@ public class SudokuFactory {
 		return createBasicEmptyRectangleSudoku(size, size);
 	}
 
+	public static void setIMMutableCells(MultiDoku doku, Map<Coordinate, Integer> immutableCells) {
+		immutableCells.forEach((coordinate, symbol) -> {
+			for (Sudoku sudoku : doku.getSubGrids()) {
+				Cell cell = sudoku.getCell(coordinate.getX(), coordinate.getY());
+				if (cell != null) {
+					cell.setSymbolIndex(symbol);
+					cell.setImmutable();
+				}
+			}
+		});
+	}
 }

app/src/main/java/sudoku/constraint/BlockConstraint.java

@@ -1,14 +1,15 @@
 package sudoku.constraint;
 
 import sudoku.Block;
+import sudoku.Cell;
 import sudoku.Sudoku;
 
 public class BlockConstraint implements IConstraint{
 
 	@Override
 	public boolean canBePlaced(final Sudoku s, int x, int y, int newSymbolIndex) {
-		Block bloc = s.getCell(x, y).getBlock();
+		Block block = s.getCell(x, y).getBlock();
-		return !bloc.containsSymbol(newSymbolIndex);
+		return !block.containsSymbol(newSymbolIndex);
 	}
 
 }

app/src/main/java/sudoku/io/SudokuSerializer.java

@@ -10,17 +10,16 @@ import sudoku.Block;
 import sudoku.Cell;
 import sudoku.ImmutableCell;
 import sudoku.MultiDoku;
-import sudoku.MutableCell;
 import sudoku.Sudoku;
 
 public class SudokuSerializer {
 
 	public static String serializeSudoku(final MultiDoku multidoku) {
-		List<Cell> cellIds = new ArrayList<>();
+		List<Cell> cellIds   = new ArrayList<>();
 		List<Block> blockIds = new ArrayList<>();
 
-		JSONObject jsonRoot = new JSONObject();
+		JSONObject jsonRoot  = new JSONObject();
-		JSONArray jsonCells = new JSONArray();
+		JSONArray jsonCells  = new JSONArray();
 		JSONArray jsonBlocks = new JSONArray();
 		JSONArray jsonSudokus = new JSONArray(multidoku.getNbSubGrids());
 
@@ -55,17 +54,16 @@ public class SudokuSerializer {
 
 		// init blocks
 
-		for (int i = 0; i < blockIds.size(); i++) {
+        for (Block blockId : blockIds) {
-			JSONObject blockJsonObject = new JSONObject();
+            JSONObject blockJsonObject = new JSONObject();
-			JSONArray cellsJsonArray = new JSONArray();
+            JSONArray cellsJsonArray = new JSONArray();
-			Block block = blockIds.get(i);
+            for (Cell cell : blockId.getCells()) {
-			for (Cell cell : block.getCells()) {
+                int cellID = cellIds.indexOf(cell);
-				int cellID = cellIds.indexOf(cell);
+                cellsJsonArray.put(cellID);
-				cellsJsonArray.put(cellID);
+            }
-			}
+            blockJsonObject.put("cellIDs", cellsJsonArray);
-			blockJsonObject.put("cellIDs", cellsJsonArray);
+            jsonBlocks.put(blockJsonObject);
-			jsonBlocks.put(blockJsonObject);
+        }
-		}
 
 		for (int i = 0; i < multidoku.getNbSubGrids(); i++) {
 			// serialise sub grid
@@ -115,7 +113,7 @@ public class SudokuSerializer {
 			if (entry.has("immutable")) {
 				cells.add(new ImmutableCell(symboleIndex));
 			} else {
-				cells.add(new MutableCell(symboleIndex));
+				cells.add(new Cell(symboleIndex));
 			}
 		}
 

app/src/main/java/sudoku/solver/Solver.java

@@ -1,23 +1,53 @@
 package sudoku.solver;
 
 import sudoku.MultiDoku;
-import sudoku.MutableCell;
+import sudoku.Cell;
-import sudoku.constraint.IConstraint;
+import sudoku.io.SudokuPrinter;
 
-import java.util.ArrayList;
 import java.util.List;
-import java.util.Random;
-import java.util.Stack;
 
 public class Solver {
-    Stack<MutableCell> stack;
 
-    public Solver() {}
+    /**
+     * Résout le multidoku passé en paramètre si c'est possible.
+     * En testant toutes les possibilités avec un algorithme de backtracking.
+     * @param doku Multidoku, à résoudre
+     * @return boolean, true s'il est résolut ou false s'il ne l'est pas.
+     */
+    public static boolean solve(MultiDoku doku) {
+        if (doku.isValid()) {
+            return true;
+        }
+
+        Cell cellToFill = doku.getFirstEmptyCell();
+        if (cellToFill == null) {
+            return false;
+        }
+
+        List<Integer> possibleSymbols = doku.getPossibleSymbolsOfCell(cellToFill);
+        if (possibleSymbols.isEmpty()) {
+            return false;
+        }
+
+        for (int symbol : possibleSymbols) {
+            cellToFill.setSymbolIndex(symbol);
+            if (Solver.solve(doku)) {
+                return true;
+            } else {
+                cellToFill.setSymbolIndex(Cell.NOSYMBOL);
+            }
+        }
+        return false;
+    }
+
+    /*
+    Ancien algo abandonné pour le moment
 
     private void rollBack() {
         stack.pop();
     }
 
+
     public MultiDoku solve(MultiDoku doku, List<IConstraint> constraints) throws Exception {
         List<MutableCell> allMutableCells = doku.getMutableCells();
         List<MutableCell> remainingCellsToCheck = new ArrayList<>(allMutableCells);
@@ -39,4 +69,6 @@ public class Solver {
         }
         return doku;
     }
+
+     */
 }

app/src/test/java/sudoku/solver/SolverTest.java

@@ -0,0 +1,85 @@
+package sudoku.solver;
+
+import org.junit.jupiter.api.Test;
+import sudoku.*;
+import sudoku.io.SudokuPrinter;
+
+import java.util.List;
+
+class SolverTest {
+
+    @Test
+    void solveTest() {
+
+        MultiDoku dokuToTest = SudokuFactory.createBasicEmptySquareSudoku(3);
+        MultiDoku dokuResult = SudokuFactory.createBasicEmptySquareSudoku(3);
+
+        Sudoku sudokuToTest = dokuToTest.getSubGrid(0);
+        Sudoku sudokuResult = dokuResult.getSubGrid(0);
+
+        int ns = Cell.NOSYMBOL;
+        List<Integer> immutableCells = List.of(ns, ns,  0, ns, ns,  2,  8, ns,  1,
+                                               ns,  3, ns, ns,  5,  6,  7, ns, ns,
+                                               ns, ns, ns,  8, ns, 7, ns, ns,  6,
+                                                0, ns,  1, ns, ns, ns, ns, ns, ns,
+                                                4,  8,  7,  5,  1, ns,  6, ns, ns,
+                                                6, ns,  3,  2, ns, ns, ns,  8,  0,
+                                               ns, ns,  6, ns, ns,  8, ns,  7,  5,
+                                                8,  0, ns,  7, ns,  5,  2, ns,  3,
+                                                5, ns, ns, ns,  3,  1,  0, ns, ns);
+
+        assert(sudokuToTest.setImmutableCellsSymbol(immutableCells));
+
+
+        SudokuPrinter.printRectangleSudoku(dokuToTest.getSubGrid(0), 3, 3);
+
+
+        List<Integer> correctCells = List.of(7,  6,  0,  3,  4,  2,  8,  5,  1,
+                                                2,  3,  8,  1,  5,  6,  7,  0,  4,
+                                                1,  4,  5,  8,  0,  7,  3,  2,  6,
+                                                0,  2,  1,  6,  8,  3,  5,  4,  7,
+                                                4,  8,  7,  5,  1,  0,  6,  3,  2,
+                                                6,  5,  3,  2,  7,  4,  1,  8,  0,
+                                                3,  1,  6,  0,  2,  8,  4,  7,  5,
+                                                8,  0,  4,  7,  6,  5,  2,  1,  3,
+                                                5,  7,  2,  4,  3,  1,  0,  6,  8);
+
+        sudokuResult.setCellsSymbol(correctCells);
+
+
+        System.out.println("\n****************************Doku Control\n");
+        SudokuPrinter.printRectangleSudoku(sudokuResult, 3, 3);
+
+
+        assert(dokuResult.isValid());
+
+        Solver.solve(dokuToTest);
+
+
+        System.out.println("\n****************************\nDoku solved");
+        SudokuPrinter.printRectangleSudoku(dokuToTest.getSubGrid(0), 3, 3);
+
+
+        assert(dokuToTest.isValid());
+
+        assert(dokuToTest.equals(dokuResult));
+
+        MultiDoku dokuToTest2 = SudokuFactory.createBasicEmptySquareSudoku(3);
+        Sudoku sudokuToTest2 = dokuToTest2.getSubGrid(0);
+
+        List<Integer> immutableCells2 = List.of(ns, ns,  0, ns, ns,  2,  8, ns,  1,
+                                                1,  3, ns, ns,  5,  6,  7, ns, ns,
+                                               ns, ns, ns,  8, ns, 7, ns, ns,  6,
+                                                0, ns,  1, ns, ns, ns, ns, ns, ns,
+                                                4,  8,  7,  5,  1, ns,  6, ns, ns,
+                                                6, ns,  3,  2, ns, ns, ns,  8,  0,
+                                               ns, ns,  6, ns, ns,  8, ns,  7,  5,
+                                                8,  0, ns,  7, ns,  5,  2, ns,  3,
+                                                5, ns, ns, ns,  3,  1,  0, ns, ns);
+        sudokuToTest2.setImmutableCellsSymbol(immutableCells2);
+
+        boolean isSolved = Solver.solve(dokuToTest2);
+
+        assert(!isSolved);
+    }
+}