Consider following singly linked list implementation taken from some online resource. insert_node_pos(int pos,int val) adds a node with value as val at position pos in the singly linked list.

struct node

{

int value;

struct node *next;

};

typedef struct node snode;

//linked list operations

snode* create_node(int);

void insert_node_first(int value);

void insert_node_last(int value);

void insert_node_pos(int position, int value);

void delete_pos();

void search(int value);

void display();

snode *newnode, *ptr, *prev, *temp;

snode *first = NULL, *last = NULL;

void insert_node_pos(int pos, int val)

{

int cnt = 0, i;

newnode = create_node(val);

ptr = first;

while (ptr != NULL) {

ptr = ptr->next;

cnt++;

}

if (pos == 1)

{

if (first == last && first == NULL)

{

first = last = newnode;

first->next = NULL;

last->next = NULL;

}

else

{

temp = first;

first = newnode;

first->next = temp;

}

printf(" Inserted");

}

else if (pos>1 && pos<=cnt)

{

ptr = first;

for (i = 1;i < pos;i++)

{

prev = ptr;

ptr = ptr->next;

}

prev->next = newnode;

newnode->next = ptr;

printf(" ----INSERTED----");

}

else

{

printf("Position is out of range");

}

}

Understand the behavior of the method insert_node_pos. Write 3 unit tests for this method. Try to cover as much of code as possible.