Need help with writing the test cases for the following code in java. public class ArrayBasedStack implements StackADT {

private T[] stackArray;

private int size;

private int capacity;

@SuppressWarnings("unchecked")

public ArrayBasedStack(int initialCapacity) {

size = 0;

this.capacity = initialCapacity;

stackArray = (T[])new Object[capacity];

}

public ArrayBasedStack() {

this(100);

}

/**

* Checks if the stack is empty.

*

* @return Returns true if the stack is empty.

*/

@Override

public boolean isEmpty() {

return size == 0;

}

/**

* Checks the item at the top of the

* stack without removing it.

*

* @return Item at the top of the stack.

*/

@Override

public T peek() throws EmptyStackException {

if (isEmpty()) {

throw new EmptyStackException();

}

return stackArray[size - 1];

}

/**

* Removes the item at the top of

* the stack.

*

* @return The item that was removed.

*/

@Override

public T pop() throws EmptyStackException {

if (isEmpty()) {

throw new EmptyStackException();

}

T result = stackArray[size - 1];

stackArray[size - 1] = null;

size--;

return result;

}

/**

* Pushes an item onto the stack.

*

* @param item

* Item to be pushed

* onto the stack.

*/

@Override

public void push(T item) {

if (size == capacity) {

expandCapacity();

}

stackArray[size] = item;

size ++;

}

/**

* Checks if an item is in the stack.

*

* @param item

* Item to be looked for.

* @return Returns true if the item is

* somewhere in the stack.

*/

@Override

public boolean contains(T item) {

for (int i = size - 1; i >= 0; i--) {

if (stackArray[i].equals(item)) {

return true;

}

}

return false;

}

/**

* Number of items in the stack.

*

* @return The number of items in

* the stack.

*/

@Override

public int size() {

return size;

}

/**

* Clears the stack (removes all of

* the items from the stack).

*/

@Override

public void clear() {

for (int i = 0; i < size; i++) {

stackArray[i] = null;

}

size = 0;

}

/**

* Returns an array with a copy of each element in the stack with the top of

* the stack being the last element

*

* @return the array representation of the stack

*/

@Override

public Object[] toArray() {

@SuppressWarnings("unchecked")

T[] copy = (T[])new Object[this.size()];

for (int i = 0; i < this.size(); i++) {

copy[i] = this.stackArray[i];

}

return copy;

}

/**

* Expands the capacity of the stack by doubling its current capacity.

*/

private void expandCapacity() {

@SuppressWarnings("unchecked")

T[] newArray = (T[])new Object[this.capacity * 2];

for (int i = 0; i < this.capacity; i++) {

newArray[i] = this.stackArray[i];

}

this.stackArray = newArray;

this.capacity *= 2;

}

/**

* Returns the string representation of the stack.

*

* [] (if the stack is empty)

* [bottom, item, ..., item, top] (if the stack contains items)

*

* @return the string representation of the stack.

*/

@Override

public String toString() {

StringBuilder builder = new StringBuilder();

builder.append('[');

boolean firstItem = true;

for (int i = 0; i < this.size(); i++) {

if (!firstItem) {

builder.append(", ");

}

else {

firstItem = false;

}

// String.valueOf will print null or the toString of the item

builder.append(String.valueOf(this.stackArray[i]));

}

builder.append(']');

return builder.toString();

}

/**

* Two stacks are equal iff they both have the same size and contain the

* same elements in the same order.

*

* @param other

* the other object to compare to this

*

* @return {@code true}, if the stacks are equal; {@code false} otherwise.

*/

@Override

public boolean equals(Object other) {

if (this == other) {

return true;

}

if (other == null) {

return false;

}

if (this.getClass().equals(other.getClass())) {

ArrayBasedStack otherStack = (ArrayBasedStack)other;

if (this.size() != otherStack.size()) {

return false;

}

Object[] otherArray = otherStack.toArray();

for (int i = 0; i < this.size(); i++) {

if (!(this.stackArray[i].equals(otherArray[i]))) {

return false;

}

}

return true;

}

return false;

}

}