Need help creating JUnit test cases for a Fisher-Yates shuffle algorithm. Below is the code, the project description and requirements, and some pseudocode. CODE:

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.FileReader;

import java.io.FileWriter;

import java.util.Random;

//Randomly gets songs from the input

//Prints them into the output

//Shuffles the songs in the output

//Reprints the songs in the output

public class Playlist

{

static String[] FYShuffling(String []array1, int d) //shuffle algorithm

{

String []list = new String[d];

String []index2 = new String[d];

for(int i = 0; i < d; i++)

index2[i] = "a";

int index;

Random rand = new Random();

for(int i = 0; i < d; i++)

{

do //while loop goes first, then condition is checked

{

index = rand.nextInt(d);

}

while(index2[index] != "a");

{

index2[index] = "b";

list[i] = array1[index];

}

}

return list;

}

public static void main(String agrs[]) throws Exception //add songs into output then shuffles it

{

String title[] = new String[20];

String shuffle[] = new String[20];

FileWriter fw = null;

BufferedWriter bw = null;

try

{

int i = 0;

fw = new FileWriter("LastNameFirstPlaylist.txt"); //output

bw = new BufferedWriter(fw);

FileReader read = new FileReader("Playlist.txt"); //input

BufferedReader bread = new BufferedReader(read);

while(bread.readLine() != null) //adds songs into output

{

title[i] = bread.readLine() + " ";

i++;

}

bread.close();

read.close();

}

catch (Exception ex)

{

System.out.println(ex);

}

shuffle = FYShuffling(title,20); //shuffles the songs in the output

for(String string2:shuffle)

{

try

{

bw.write(string2);

}

catch(Exception ex)

{

}

System.out.println(string2); //prints back shuffled songs

}

bw.close();

fw.close();

}

} Description and Requirements: You are planning a road trip and want to create a playlist of your favorite songs. Assume that the song titles are in an array of strings. Create a shuffle of your songs (permutation of your original songs). Use the FisherYates shuffle algorithm that works in O(n) running time. We will use a method that creates pseudo-random numbers (see end for help) in O(1) running time. The basic idea is to start from the last element, swap it with a randomly selected element from the whole array (including last). In the next step you will consider the array from 0 to n-2 (size reduced by 1), and repeat the process until you reach the first element. Pseudocode:

To compare two text files in Junit, you can try the following pseudocode.

Use BufferedReader to read the input files.

BufferedReader Out=new BufferedReader (new FileReader ());

BufferedReader In=new BufferedReader (new FileReader ());

while ((expectedLine = In.readLine ()) != null) { String actualLine = Out.readLine ();

assertEquals (expectedLine, actualLine); }

Set seed value as 20.

Random r=new Random();

r.setSeed(20);

Compare the output file with attached see next:

if you use

double d = random.nextDouble();

int j = (int)(d*arr.length);

use Target1.txt

else if you use

Random r = new Random(0);

r.setSeed(20);

for (i = n-1 to 0) {

int j = r.nextInt(i);

swap(arr[i],arr[j]);

}

use Target2.txt. Target 1: https://www.dropbox.com/s/bowpp67vsmp01sx/Target1.txt?dl=0 Target 2: https://www.dropbox.com/s/ysnujma2lxika8m/Target2.txt?dl=0 Playlist: https://www.dropbox.com/s/75ouou9flfqt1vr/Playlist.txt?dl=0 Both Target.txts are just a list of songs to compare to. Playlist is the list of given songs to use. LastNameFirstPlaylist is the shuffled playlist that you're using to compare to either Target1 or Target2.