### Question:
Matrix implements Serializable { public static Matrix zeros(@NonNull int... shape) { checkNotNull(shape); checkExpression( shape.length == 2, "Shape is incorrect"); return new Matrix(new double[shape[0] * shape[1]], shape[0], shape[1]); } private  Matrix(double[] array, int row, int  col); int[] shape(); double[] getArray(); double[][] getArrays(); Matrix copy(); int getRow(); int getCol(); double get(int i, int j); void set(int i, int j, double value); Matrix times(@NonNull Matrix matrix); Matrix times(double num); Matrix timesTo(double num); Matrix timesTo(@NonNull Matrix matrix); Matrix plus(@NonNull Matrix matrix); Matrix plusTo(@NonNull Matrix matrix); Matrix minus(@NonNull Matrix matrix); Matrix minusTo(@NonNull Matrix matrix); Matrix dot(@NonNull Matrix matrix); Matrix transpose(); static Matrix array(@NonNull double[][] arrays); static Matrix array(@NonNull double[] array, int row); static Matrix randn(int row, int col); static Matrix plus(@NonNull Matrix a, @NonNull Matrix b); static Matrix plusTo(@NonNull Matrix a,@NonNull Matrix b); static Matrix minus(@NonNull Matrix a,@NonNull Matrix b); static Matrix minusTo(@NonNull Matrix a, @NonNull Matrix b); static Matrix times(@NonNull Matrix a, @NonNull Matrix b); static Matrix times(@NonNull Matrix matrix, double num); static Matrix timesTo(@NonNull Matrix matrix, double num); static Matrix timesTo(@NonNull Matrix a, @NonNull Matrix b); static Matrix dot(@NonNull Matrix a, @NonNull Matrix b); static Matrix transpose(@NonNull Matrix a); static Matrix zeroLike(Matrix matrix); static Matrix zeros(@NonNull int... shape);  }### Answer:
@Test public void testZeros() { final Matrix matrix = Matrix.zeros(2, 3); assertEquals(matrix.getRow(), 2); assertEquals(matrix.getCol(), 3); assertArrayEquals(matrix.getArray(), new double[]{ 0D, 0D, 0D, 0D, 0D, 0D }, 0); }