JUnit - Writing Sample Test Cases for StudentService in Java

public class Student {
    public Student(String studentName, int studentId,
                   String courseName, double gpa)
    {
        super();
        this.studentName = studentName;
        this.studentId = studentId;
        this.courseName = courseName;
        this.gpa = gpa;
    }
    public Student()
    {
        // via setter methods, rest fields are done
    }
    String studentName;
    int studentId;
    String courseName;
    double gpa;
    public String getStudentName() { return studentName; }
    public void setStudentName(String studentName)
    {
        this.studentName = studentName;
    }
    public int getStudentId() { return studentId; }
    public void setStudentId(int studentId)
    {
        this.studentId = studentId;
    }
    public String getCourseName() { return courseName; }
    public void setCourseName(String courseName)
    {
        this.courseName = courseName;
    }
    public double getGpa() { return gpa; }
    public void setGpa(double gpa) { this.gpa = gpa; }
}

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

public class StudentServicesJava {
    
    // Appending i.e. adding students at the end of the
    // list and returning the studentlist size
    public int appendStudent(Student student,List<Student> studentList) 
    {
        studentList.add(student);        
        return studentList.size();
    }
  
    // Inserting i.e. inserting students at the middle
    // of the list and returning the studentlist size
    public int insertStudent(Student student,List<Student> studentList,int index) 
    {
        studentList.add(index,student);        
        return studentList.size();
    }
  
    // Removing students from the list and 
    // returning the studentlist size
    public int removeStudent(List<Student> studentList,int index) 
    {
        studentList.remove(index);        
        return studentList.size();
    }
  
    // Returning the studentlist size
    public int getStudents(List<Student> studentList) {
        return studentList.size();
    }
  
    // Retrieving the student name at the specified index
    public String getStudentName(List<Student> studentList,int index) {
        return studentList.get(index).getStudentName();
    }
  
    // Returning the student list who matches for a specific course
    public List<Student> getStudentsByCourseWise(List<Student> studentList,String courseName) {
        List<Student> courseWiseStudents = new ArrayList<Student>();
        for (int i = 0; i < studentList.size(); i++) {
            if (studentList.get(i).getCourseName().equalsIgnoreCase(courseName)) {
                courseWiseStudents.add(studentList.get(i));
            }
        }
        return courseWiseStudents;
    }
  
    // Returning the student list who matches for a specific gpa and more
    public List<Student> getStudentsByGPA(List<Student> studentList,double gpa) {
        List<Student> gpaWiseStudents = new ArrayList<Student>();
        for (int i = 0; i < studentList.size(); i++) {
            if (studentList.get(i).getGpa() >= gpa) {
                gpaWiseStudents.add(studentList.get(i));
            }
        }
        return gpaWiseStudents;
    }

}

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

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

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

public class TestStudentServicesJava {
    List<Student> studentList = new ArrayList<Student>();
    StudentServicesJava studentServicesJavaObject = new StudentServicesJava();

    @DisplayName("Test check for adding/inserting/filtering by coursewise or gpawise/removing students ")
    @Test
    public void testCheckForAdditionAndDeletion() {
        
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 0);
        
        // creating a student object
        Student student = new Student();
        student.setStudentId(1);
        student.setStudentName("Rachel");
        student.setCourseName("Java");
        student.setGpa(9.2);
        studentServicesJavaObject.appendStudent(student, studentList);
        
        // After appending the data
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 1);
        Student monica = new Student("Monica", 2, "Java", 8.5);
        studentServicesJavaObject.insertStudent(monica, studentList, 0);
        
        // After inserting the data
        assertEquals(true, studentServicesJavaObject.getStudentName(studentList,0).equalsIgnoreCase("Monica"));
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 2);
        Student phoebe = new Student("Phoebe", 3, "Python", 8.5);
        studentServicesJavaObject.appendStudent(phoebe, studentList);
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 3);
        assertEquals(true, studentServicesJavaObject.getStudentName(studentList,1).equalsIgnoreCase("Rachel"));
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == studentList.size());
        
        // checking according to coursewise, first check for java
        List<Student> javaCourseWiseStudentList = new ArrayList<Student>();
        javaCourseWiseStudentList = studentServicesJavaObject.getStudentsByCourseWise(studentList, "java");
        
        // As for java, only 2 students are entered and checking like below
        assertEquals(true, studentServicesJavaObject.getStudents(javaCourseWiseStudentList) == 2);
        assertEquals(true, studentServicesJavaObject.getStudentName(javaCourseWiseStudentList,1).equalsIgnoreCase("Rachel"));
        
        List<Student> pythonCourseWiseStudentList = new ArrayList<Student>();
        pythonCourseWiseStudentList = studentServicesJavaObject.getStudentsByCourseWise(studentList, "python");
        
        // As for python, only 1 student is entered and checking like below
        assertEquals(true, studentServicesJavaObject.getStudents(pythonCourseWiseStudentList) == 1);
        assertEquals(true, studentServicesJavaObject.getStudentName(pythonCourseWiseStudentList,0).equalsIgnoreCase("phoebe"));
        
        // php course check
        List<Student> phpCourseWiseStudentList = new ArrayList<Student>();
        phpCourseWiseStudentList = studentServicesJavaObject.getStudentsByCourseWise(studentList, "unknown");
        
        // As for php, no students are there, we need to check like below
        assertEquals(true, studentServicesJavaObject.getStudents(phpCourseWiseStudentList) == 0);
        
        // Now with gpa check
        List<Student> gpaWiseStudentList = new ArrayList<Student>();
        gpaWiseStudentList = studentServicesJavaObject.getStudentsByGPA(studentList, 9.0);
        
        // Above 9.0, only 1 student is having
        assertEquals(true, studentServicesJavaObject.getStudents(gpaWiseStudentList) == 1);
        assertEquals(true, studentServicesJavaObject.getStudentName(gpaWiseStudentList,0).equalsIgnoreCase("rachel"));
        
        List<Student> higherGpaWiseStudentList = new ArrayList<Student>();
        higherGpaWiseStudentList = studentServicesJavaObject.getStudentsByGPA(studentList, 9.5);
        
        // Above 9.5, no students are there
        assertEquals(true, studentServicesJavaObject.getStudents(higherGpaWiseStudentList) == 0);
        
        // let us remove the students
        studentServicesJavaObject.removeStudent(studentList, 0);
        
        // As 0th index student got removed, only 2 students remain
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 2);
        
        // As 0th index got removed, rachel will be at 0th index
        assertEquals(true, studentServicesJavaObject.getStudentName(studentList,0).equalsIgnoreCase("Rachel"));
        
        studentServicesJavaObject.removeStudent(studentList, 1);
        
        // As 1st index student got removed, only 1 student remain
        assertEquals(true, studentServicesJavaObject.getStudents(studentList) == 1);
        
        // As 1st index got removed, like before rachel will be at 0th index
        assertEquals(true, studentServicesJavaObject.getStudentName(studentList,0).equalsIgnoreCase("Rachel"));
        
    }

}