I need help with writing tests for class Point according to these specifications below

Test cases for Constructors

#	Test Cases	Expected Result
1	Point p = new Point();	getX() should return 0 getY() should return 0
2	Point p = new Point(5,10);	getX() should return 5 getY() should return 10
3	Point p = new Point (5,10);	getX() should return 5 getY() should return 10
4	new Point( );	should throw IllegalArgumentException
5	Point p = new Point (5,10); Point q = new Point(p);	getX() for q should return 5 getY() for q should return 10
6	Point p; Point q = new Point(p);	should throw NullPointerException

Test cases for toString()

#	Test Cases	Expected Result
1	Point p = new Point(5,10) p.toString()	(5,10)
2	Strng str = 3,7; Point p = new Point(str) p.toString()	(3,7)
3	Point p = new Point(5,10); Point q = new Point(p); q.toString()	(5,10)

Test cases for equals()

#	Test Cases	Expected Result
1	Point p = new Point(5,10) p.equals(null)	false
2	Point p = new Point(5,10) Point q = new Point(5,10) p.equals(q)	true
3	Point p = new Point(5,10) Point q = new Point(10,5) p.equals(q)	false

Test cases for manhattanDistance()

#	Test Cases	Expected Result
1	Point p = new Point(10,15) p.manhattanDistance(p)	0
2	Point p = new Point(5,7) Point q = new Point(10,15) p.manhattanDistance(q)	13
3	Point p = new Point(5,7) Point q = new Point(0,0) p.manhattanDistance(q)	12
4	Point p = new Point(5,7) Point q = new Point(0,-5) p.manhattanDistance(q)	17

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This is my code;

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public class Point {

private int x; private int y;

/** * Initializes a newly created Point object with x and y * coordinates set to 0. */ public Point() {

}

/** * Initializes a newly created Point object with the given * values. * * @param x the x coordinate of this point * @param y the y coordinate of this point */ public Point(int x, int y) { this.x = x; this.y = y; }

/** * Initializes a newly created Point object with the values * from the input string. Throws an IllegalArgumentException * if parameter str is a null reference or contains more * than two values; sets both instance variables to zero if * str contains nothing but space characters. * * @param str string containing values of coordinates, such * as "10,20". */ public Point(String str) { String arr[] = str.split(","); this.x = Integer.parseInt(arr[0]); this.y = Integer.parseInt(arr[1]);

}

/** * Initializes a newly created Point object with the values * from the input Point object. * * @param other a Point object used to initialize this Point * object */ public Point(Point other) { this.x = other.x; this.y = other.y; }

/** * Returns the x coordinate of this Point object. * * @return the x coordinate of this object. */ public int getX() { return x; }

/** * Returns the y coordinate of this Point object. * * @return the y coordinate of this object. */ public int getY() { return y; }

/** * Returns a String object that represents this Point as, * for example, (5, 3) if x is 5 and y is 3. * * @return a string representation of this Point's value. */ public String toString() {

return "(" + x + "," + y + ")"; }

/** * Compares this object to the other object. The result is * true if and only if the argument is not null and is a * Point object that contains the same values as this Point * object. * * @param obj the object to compare with. * * @return true if the objects are the same; false * otherwise. */

public boolean equals(Object other) { if (this == other) return true; if (other == null) return false; if (getClass() != other.getClass()) return false; Point pt = (Point) other; if (x != pt.x) return false; if (y != pt.y) return false; return true; }

/** * Returns the Manhattan distance between this Point object * and the other Point object. * * Manhattan distance is the distance between two points if * you walk only in a horizontal or vertical direction. * * @param other the other Point object * * @return the Manhattan distance between this and other * Point objects. */ public int manhattanDistance(Point other) { int x = Math.abs(this.x - other.x);

int y = Math.abs(this.y - other.y);

return (x + y); }

}