Solution: Passing students list

fun List<Student>.makePassingStudentsList(): String = this .filter { it.pointsInSemester > 15 && it.result >= 50 } .sortedWith(compareBy({ it.surname }, { it.name })) .joinToString(separator = "\n") { "${it.name} ${it.surname}, ${it.result}" }

import org.junit.Test import kotlin.test.assertEquals fun List<Student>.makePassingStudentsList(): String = this .filter { it.pointsInSemester > 15 && it.result >= 50 } .sortedWith(compareBy({ it.surname }, { it.name })) .joinToString(separator = "\n") { "${it.name} ${it.surname}, ${it.result}" } data class Student( val name: String, val surname: String, val result: Double, val pointsInSemester: Int ) class PassingStudentsListTest { val internshipStudent = Student("Marc", "Smith", 87.0, 32) val studentWithTooLowResultToInternship = Student("Marcus", "Smith", 37.0, 32) val studentWithNotEnoughPointsForInternship = Student("Marcello", "Smith", 87.0, 12) val studentNotPassingBecauseOfResult = Student("Peter", "Jackson", 21.0, 24) val studentNotPassingBecauseOfPoints = Student("Michael", "Angelo", 71.0, 12) val allStudents = listOf( internshipStudent, studentWithTooLowResultToInternship, studentWithNotEnoughPointsForInternship, studentNotPassingBecauseOfResult, Student("Noely", "Peterson", 91.0, 22), studentNotPassingBecauseOfPoints, Student("Noe", "Samson", 41.0, 18), Student("Timothy", "Johnson", 51.0, 15), Student("Noe", "Peterson", 91.0, 22), Student("Ester", "Adams", 81.0, 30), Student("Dior", "Angel", 88.5, 38), Student("Naja", "Marcson", 100.0, 31), Student("Oregon", "Dart", 85.5, 30), Student("Ron", "Peters", 89.0, 31), Student("Harry", "Potter", 80.0, 30), Student("Sansa", "Stark", 49.5, 14), Student("Jamme", "Lannister", 80.0, 30), Student("Alex", "Nolan", 86.0, 33), Student("Jon", "Johnson", 85.1, 31), Student("James", "Johnson", 85.2, 31), Student("Jack", "Johnson", 85.3, 31) ) @Test fun `Single student that matches criteria is displayed`() { val text = listOf(internshipStudent).makePassingStudentsList() val expected = "Marc Smith, 87.0" assertEquals(expected, text) } @Test fun `Single student with too low result doesn't get internship`() { val text = listOf(studentNotPassingBecauseOfResult).makePassingStudentsList() assertEquals("", text) } @Test fun `15 points is not acceptable`() { val student = Student("Noely", "Peterson", 81.0, 15) val text = listOf(student).makePassingStudentsList() assertEquals("", text) } @Test fun `result 50 points is acceptable`() { val student = Student("Noely", "Peterson", 50.0, 25) val text = listOf(student).makePassingStudentsList() assertEquals("Noely Peterson, 50.0", text) } @Test fun `Students are displayed in an alphanumerical order sorted by surname and then by name`() { val students = listOf( Student(name = "B", surname = "A", result = 81.0, pointsInSemester = 16), Student(name = "B", surname = "B", result = 82.0, pointsInSemester = 16), Student(name = "A", surname = "A", result = 83.0, pointsInSemester = 16), Student(name = "A", surname = "B", result = 84.0, pointsInSemester = 16) ) // When val text = students.makePassingStudentsList() // Then val expected = """ A A, 83.0 B A, 81.0 A B, 84.0 B B, 82.0 """.trimIndent() assertEquals(expected, text) } @Test fun `Single student with not enough doesn't get internship`() { val text = listOf(studentNotPassingBecauseOfPoints).makePassingStudentsList() assertEquals("", text) } @Test fun `Complex test`() { val text = allStudents.makePassingStudentsList() val expected = """ Ester Adams, 81.0 Dior Angel, 88.5 Oregon Dart, 85.5 Jack Johnson, 85.3 James Johnson, 85.2 Jon Johnson, 85.1 Jamme Lannister, 80.0 Naja Marcson, 100.0 Alex Nolan, 86.0 Ron Peters, 89.0 Noe Peterson, 91.0 Noely Peterson, 91.0 Harry Potter, 80.0 Marc Smith, 87.0 """.trimIndent() assertEquals(expected, text) } }