Junit5 how to count employees in UnitTest-CodePudding

So I have 3 packages, Implementation, interfaces and test. I want to write the functionality into EmployeeImp so my unit test passes without error when I run it on TestEmployeeImp. However I'm not sure how getEmployeeCount is written as it fails in the unit test. I tried to solve it by creating the int count but it doesn't work. I know I need to use the array list to count the number of employees but I cannot come up with a solution and I can't find any samples of code that are like my unit test. If anyone can help it would be very appreciated.

//EmployeeImp

import java.util.ArrayList;
import java.util.List;

import interfaces.Employer;
import interfaces.Person;

public class EmployerImpl implements Employer {
    
    private String name;
    private List<Person> employees;
    private int count;


    public EmployerImpl(String n) {
        //gets name
        this.name = n;
        //Array List
        employees = new ArrayList<Person>();
        // TODO Auto-generated constructor stub
    }

    @Override
    public void hire(Person p, String title, double salary) {
        p.setJob(null);
        employees.add(p);

    }

    @Override
    public List<Person> getEmployees() {
        //Returns Employees in a List
        return employees;
    }

    @Override
    public int getEmployeeCount() {
        return this.count;
        //Returns employees size
        
        
    }

    @Override
    public boolean fire(Person p) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public String getName() {
        //returns name
        return name;
    }

    @Override
    public boolean isEmployed(Person p) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public Person getHighestPaid() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Person getLowestPaid() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public double getStaffCost() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public int getCountOf(String title) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public List<Person> getAll(String title) {
        // TODO Auto-generated method stub
        return null;
    }

}

//Employer.java
import java.util.List;

public interface Employer {

    void hire(Person p, String title, double salary);
    List<Person> getEmployees();
    int getEmployeeCount();
    boolean fire(Person p);
    String getName();
    boolean isEmployed(Person p);
    Person getHighestPaid();
    Person getLowestPaid();
    double getStaffCost();
    int getCountOf(String title);
    List<Person> getAll(String title);
}

//TestEmployeeImp

import static org.junit.jupiter.api.Assertions.*;

import java.util.ArrayList;
import java.util.List;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import implementation.EmployerImpl;
import implementation.PersonImpl;
import interfaces.Employer;
import interfaces.Person;

class TestEmployerImpl {

    private Employer e;
    private Person highest;
    private Person lowest;
    
    @BeforeEach
    void setUp() throws Exception {
        e = new EmployerImpl("NCCO");
        lowest = new PersonImpl("John", 18);
        e.hire(lowest, "Lab Assistant", 20000);
        highest = new PersonImpl("Anu", 50);
        e.hire(highest, "Best Teacher", 80000);
        e.hire(new PersonImpl("Damien", 18), "Teacher", 41000);
        e.hire(new PersonImpl("Malachy", 45), "Teacher", 50000);
        
    }

    @Test
    void testGetEmployees() {
        List<Person> l = e.getEmployees();
        assertNotNull(l);
        assertEquals(4, l.size());
    }

    @Test
    void testGetEmployeeCount() {
        assertEquals(4, e.getEmployeeCount());
        Person p = new PersonImpl("Paul H", 50);
        e.hire(p, "teacher", 1000);
        assertEquals(5, e.getEmployeeCount());
        e.fire(p);
        assertEquals(4, e.getEmployeeCount());
    }

    @Test
    void testFire() {
        Person p = new PersonImpl("Damien", 18);
        boolean f= e.fire(p);
        assertTrue(f);
        assertEquals(3, e.getEmployeeCount());
        
        p = new PersonImpl("Danika", 23);
        f = e.fire(p);
        assertFalse(f);
    }

    @Test
    void testGetName() {
        assertEquals("NCCO", e.getName());
    }

    @Test
    void testIsEmployed() {
        Person p = new PersonImpl("Damien", 18);
        assertTrue(e.isEmployed(p));
        
        p = new PersonImpl("Danika", 23);
        assertFalse(e.isEmployed(p));
    }
    
    @Test
    public void testGetHighestPaid() {
        assertEquals(highest, e.getHighestPaid());
    }

    @Test
    void getLowestPaid() {
        assertEquals(lowest, e.getLowestPaid());
    }

    @Test
    void getStaffCost() {
        assertEquals(191000, e.getStaffCost());
    }
    
    @Test
    void testGetCountOf() {
        assertEquals(2, e.getCountOf("Teacher"));
        assertEquals(0, e.getCountOf("Awesome Teacher"));
    }
    
    @Test 
    void testGetAll(){
        assertEquals(2, e.getAll("Teacher").size());
        assertNotNull(e.getAll("Dean"));
        assertTrue(e.getAll("Dean").isEmpty());
    }

}

CodePudding user response：

I can't see any code which initialize or increment int count variable. But as you said, you don't need count variable and just use size() method in employees List

@Override
public int getEmployeeCount() {
    return this.employees.size();
}

CodePudding user response：

In @BeforeEach you're test by creating 4 employees.

Your hire method does 'employees.add(p);' , so it expands your list.
Your fire method does not do anything, just returning false.

Yet you expect in test testFire and testGetEmployeeCount that the number of employees has decreased. That does not happen and will fail.

You need the following fix: IMPORTANT - Implement an equals and hash code on your PersonImpl class (so you can compare equal objects content instead of object-hash value). You can use guava or apache commmons or lombok or any other way to do that.

Then implement in 'fire' method:

    @Override
    public boolean fire(Person p) {
        return employees.remove(p);
    }

In this case I assume you will implement limitations in the 'hire' method on your class to have duplicate employees, so you need only to remove it once. If employees can be duplicate, then do to remove the employee including duplicates:

return employees.removeAll(Collections.singletonList(p));