Making sure application is up to spec

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

@@ -20,10 +20,18 @@ public class Solver implements SudokuSolver {
         this.board = board;
     }
 
-    /** {@inheritDoc} */
+    /**
+     * {@inheritDoc}
+     * <p>
+     * Note that this returns a copy of the board, not the actual board
+     */
     @Override
     public int[][] getBoard() {
-        return board;
+        int[][] copy = new int[9][9];
+        for (int row = 0; row < 9; row++) {
+            System.arraycopy(board[row], 0, copy[row], 0, 9);
+        }
+        return copy;
     }
 
     /** Resets the board to all zeros */
@@ -34,7 +42,6 @@ public class Solver implements SudokuSolver {
                 row[i] = 0;
             }
         }
-        // board = new int[9][9];
     }
 
     /* {@inheritDoc} */

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

@@ -17,8 +17,12 @@ class SolverTest {
         Solver solver = new Solver();
         int[][] board = new int[9][9];
         solver.setBoard(board);
-        assertEquals(board, solver.getBoard());
+
+        for (int row = 0; row < 9; row++) {
+            assertArrayEquals(board[row], solver.getBoard()[row]);
         }
+    }
+    
 
     @Test
     void randomizeBoardTest() {
@@ -28,6 +32,12 @@ class SolverTest {
         assertNotEquals(board, solver.getBoard());
     }
 
+    @Test
+    void emptyTest() {
+        Solver solver = new Solver();
+        assertTrue(solver.solve());
+    }
+
     @Test
     void legalTest() {
         Solver solver = new Solver();