JAVA Command Line Program - How can I write a unit test for this program?
package com.company;
import java.util.*;
import java.util.stream.Collectors;
public class Data {
public String first;
public String last;
public int age;
public int id;
public String country;
public Data(String first, String last, int age, int id, String country) {
this.first = first;
this.last = last;
this.age = age;
this.id = id;
this.country = country;
}
public String toString() {
return "{" +
" 'firstName': " + first + "," +
" 'lastName': " + last + "," +
" 'age': " + age + "," +
" 'id': " + id + "," +
" 'country': " + country +
" }";
}
public static ArrayList getData(int numRows) {
ArrayList generator = new ArrayList<>();
String[] names = {"James", "Matt", "Olivia", "Liam", "Charlotte", "Amelia", "Evelyn", "Taeyeon", "Sooyoung", "Tiffany", "Yoona", "Hayley"};
String[] lastName = {"Novak", "Forbis", "Corner", "Broadbet", "Kim", "Young", "Hwang", "Choi", "McDonalds", "Kentucky", "Holmes", "Shinichi"};
String[] country = {"New Zealand", "Vietnam", "Korea", "French", "Japan", "Switzerland", "Italy", "Spain", "Thailand", "Singapore", "Malaysia", "USA"};
String data = "";
Random ran = new Random();
int namesLength = numRows; // passing length to names_len
int lastNameLength = lastName.length; // passing length to lastname_len
int countryLength = country.length; // passing length to lastname_len
for (int i = 0; i < numRows; i++) { // for loop to iterate upto names.length
int x = ran.nextInt(namesLength); // generating random integer
int y = ran.nextInt(lastNameLength); // generating random integer
int z = ran.nextInt(countryLength);
int a = ran.nextInt(40);
int exampleId = ran.nextInt(1000);
// below for loop is to remove that element form names array
for (int j = x; j < (namesLength - 1); j++) {
names[j] = names[j + 1]; // this moves elements to one step back
}
// below for loop is to remove that element form Lastnames array
for (int j = y; j < (lastNameLength - 1); j++) {
lastName[j] = lastName[j + 1]; // this moves elements to one step back
}
for (int j = z; j < (countryLength - 1); j++) {
country[j] = country[j + 1]; // this moves elements to one step back
}
namesLength = namesLength - 1; // reducing len of names_len by 1
lastNameLength = lastNameLength - 1; // reducing len of lastname_len by 1
countryLength = countryLength - 1; // reducing len of lastname_len by 1
// Output data in NDJSON format
data = "{" +
" 'firstName': " + names[x] + "," +
" 'lastName': " + lastName[y] + "," +
" 'age': " + a + "," +
" 'id': " + exampleId + "," +
" 'country': " + country[z] +
" }";
System.out.println(data);
generator.add(new Data(names[x], lastName[y], a, exampleId, country[z])); }
// return a list of data
return generator;
}
public static void main(String[] args) {
// Generate random data
int rows = 0;
Scanner sc = new Scanner(System.in);
System.out.print("Enter number of rows (maximum 12) you want to generate: ");
rows = sc.nextInt();
while (rows >= 13 || rows <= 0) {
System.out.println("Rows must be in range of 1 and 12");
System.out.print("Please reenter the number of rows: ");
rows = sc.nextInt();
}
System.out.println("Data is now generated\n");
ArrayList generatedData = getData(rows);
int input = 0;
sc.nextLine();
System.out.println("Move to Task 2\n");
String options =
"What would you like to do next?\n" +
"1 - Find the oldest person in the dataset\n" +
"2 - Find the youngest person in the dataset\n" +
"3 - Group data by country and find the total number of country\n" +
"4 - Exit";
System.out.println(options);
input = sc.nextInt();
while (input >= 5 || input < 0) {
System.out.println("Please enter the valid option");
System.out.print("Please reenter the option: ");
input = sc.nextInt();
}
if (input == 4) {
System.out.println("Exit the program\n");
return;
}
if (input == 1) {
// Find oldest
Data oldest = generatedData.stream().max((a, b) -> a.age - b.age).get();
System.out.println(String.format("The oldest person is %s %s", oldest.first, oldest.last));
} else if (input == 2) {
// Find youngest
Data youngest = generatedData.stream().min((a, b) -> a.age - b.age).get();
System.out.println(String.format("The youngest person is %s %s", youngest.first, youngest.last));
} else if (input == 3) {
//Group by country and return count
Map> countryGrouped =
generatedData.stream().collect(Collectors.groupingBy(w -> w.country));
System.out.println(String.format("Data is grouped by country: %s\n", countryGrouped));
System.out.println(String.format("Total of country: %s\n", countryGrouped.size()));
}
}
}