How to create NUnit testing for a method with "switch case"?

Question

I'm brand new in NUnit testing. Here I've a problem. I've a method with "switch case ... default". What is best method to write a unit testing for that method. Here i'm coping the method.

using System;
using System.IO;
using System.Text;

namespace Exercise3
{
public class Exercise2
{
public void ipk()
{
double nim;
string nama, kelas;
string namaFile;
string[] mk = new string[6];
string[] nilHuruf = new string[6];
double[] nilAngka = new double[6];

        try
        {
            Console.Write("Nama File : ");
            namaFile = Convert.ToString(Console.ReadLine());

            Console.WriteLine("=================IPK=================");
            Console.WriteLine("=====================================");
            Console.Write("Masukkan NIM: ");
            nim = Convert.ToDouble(Console.ReadLine());
            Console.Write("Masukkan Nama: ");
            nama = Convert.ToString(Console.ReadLine());
            Console.Write("Masukkan Kelas: ");
            kelas = Convert.ToString(Console.ReadLine());
            Console.WriteLine("\n-------------------------------------");

            for (int i = 0; i < 6; i++)
            {
                Console.Write("Masukkan Nama Matakuliah: ");
                mk[i] = Convert.ToString(Console.ReadLine());
                Console.Write("Masukkan Nilai Angka: ");
                nilAngka[i] = Convert.ToDouble(Console.ReadLine());
                Console.Write("Masukkan Nilai Huruf: ");
                nilHuruf[i] = Convert.ToString(Console.ReadLine());
                Console.WriteLine();
            }

            StreamWriter sw = new StreamWriter("D:\\UMY\\TI Sem 2\\Pengembangan Aplikasi Windows\\Activity\\Exercise3\\IPK.txt");

            sw.WriteLine("\n-------------------------------------");
            sw.WriteLine("Transkip Kuliah");
            sw.WriteLine("-------------------------------------\n");
            sw.WriteLine("NIM: {0}", nim);
            sw.WriteLine("Nama: {0}", nama);
            sw.WriteLine("Kelas: {0}", kelas);
            sw.WriteLine("-------------------------------------\n");
            sw.WriteLine("Transkip Mahasiswa dengan NIM: {0}", nim);
            sw.WriteLine("-------------------------------------");
            sw.WriteLine("Mata Kuliah \tNilai Angka \tNilai Huruf");
            sw.WriteLine();
            for (int i = 0; i < 6; i++)
            {
                sw.WriteLine("" + mk[i] + "\t\t" + nilAngka[i] + "\t\t" + nilHuruf[i]);
            }
            sw.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception : " + e.Message);
        }
        finally
        {
            Console.WriteLine("Executing finally block.");
        }
    }

    public void KartuKeluarga()
    {
        string[] nama, pendidikan, status;
        int input;
        string namaFile;

        try
        {
            Console.Write("Nama File : ");
            namaFile = Convert.ToString(Console.ReadLine());

            Console.WriteLine("============Kartu Keluarga============");
            Console.WriteLine("======================================");
            Console.Write("Masukkan Jumlah Anggota Keluarga: ");

            input = Convert.ToInt32(Console.ReadLine());
            nama = new string[input];
            pendidikan = new string[input];
            status = new string[input];
            for (int i = 0; i < input; i++)
            {
                Console.Write("Masukkan Nama Lengkap: ");
                nama[i] = Convert.ToString(Console.ReadLine());
                Console.Write("Masukkan Pendidikan Terakhir: ");
                pendidikan[i] = Convert.ToString(Console.ReadLine());
                Console.Write("Masukkan Status: ");
                status[i] = Convert.ToString(Console.ReadLine());
                Console.WriteLine();
            }

            StreamWriter sw = new StreamWriter("D:\\UMY\\TI Sem 2\\Pengembangan Aplikasi Windows\\Activity\\Exercise3\\Kartu Keluarga.txt");

            sw.WriteLine("Data Kartu Keluarga \n-------------------- \nNama Lengkap \tPendidikan Terakhir \tStatus");

            for (int i = 0; i < input; i++)
            {
                sw.WriteLine("" + nama[i] + "\t\t\t" + pendidikan[i] + "\t\t\t\t" + status[i]);
            }
            sw.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception : " + e.Message);
        }
        finally
        {
            Console.WriteLine("Executing finally block.");
        }
    }
    static void Main(string[] args)
    {
        Exercise2 ex = new Exercise2();
        string ulang;
        do
        {
            Console.WriteLine("===============Menu Utama===============");
            Console.WriteLine("========================================");
            Console.WriteLine("1. IPK \n2. Kartu Keluarga");
            Console.WriteLine("========================================");
            int pilih;
            Console.Write("Silahkan Pilih Menu: ");
            pilih = Convert.ToInt32(Console.ReadLine());
            switch (pilih)
            {
                case 1:
                    Console.Clear();
                    ex.ipk();
                    break;
                case 2:
                    Console.Clear();
                    ex.KartuKeluarga();
                    break;
            }
            Console.Write("Apakah ingin kembali ke menu utama? (Y/N)");
            ulang = Convert.ToString(Console.ReadLine());
            Console.Clear();
        } while (ulang == "Y" || ulang == "y");
    }
}

}