Solution: Best students list
fun List<Student>.makeBestStudentsList(): String = this
.filter { it.pointsInSemester >= 30 && it.result >= 80 }
.sortedByDescending { it.result }
.zip(INTERNSHIPS)
.sortedWith(compareBy({ it.first.surname },{ it.first.name }))
.joinToString(separator = "\n") {(student, internship)->
"${student.name} ${student.surname}, $$internship"
}
private val INTERNSHIPS =
List(1) { 5_000 } + List(3) { 3_000 } + List(6) { 1_000 }
Example solution in playground
import org.junit.Test
import kotlin.test.assertEquals
fun List<Student>.makeBestStudentsList(): String = this
.filter { it.pointsInSemester >= 30 && it.result >= 80 }
.sortedByDescending { it.result }
.zip(INTERNSHIPS)
.sortedWith(compareBy({ it.first.surname },{ it.first.name }))
.joinToString(separator = "\n") {(student, internship)->
"${student.name} ${student.surname}, $$internship"
}
private val INTERNSHIPS =
List(1) { 5_000 } + List(3) { 3_000 } + List(6) { 1_000 }
data class Student(
val name: String,
val surname: String,
val result: Double,
val pointsInSemester: Int
)
class BestStudentsListTest {
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 gets biggest internship`() {
val text = listOf(internshipStudent).makeBestStudentsList()
val expected = "Marc Smith, \$5000"
assertEquals(expected, text)
}
@Test
fun `Single student with too low result doesn't get internship`() {
val text = listOf(studentWithTooLowResultToInternship).makeBestStudentsList()
assertEquals("", text)
}
@Test
fun `Result 80 is acceptable`() {
val student = Student("Noely", "Peterson", 80.0, 32)
val text = listOf(student).makeBestStudentsList()
assertEquals("Noely Peterson, \$5000", text)
}
@Test
fun `30 points is acceptable`() {
val student = Student("Noely", "Peterson", 81.0, 30)
val text = listOf(student).makeBestStudentsList()
assertEquals("Noely Peterson, \$5000", text)
}
@Test
fun `Single student with not enough doesn't get internship`() {
val text = listOf(studentWithNotEnoughPointsForInternship).makeBestStudentsList()
assertEquals("", text)
}
@Test
fun `Complex test`() {
val text = allStudents.makeBestStudentsList()
val expected = """
Ester Adams, ${'$'}1000
Dior Angel, ${'$'}3000
Oregon Dart, ${'$'}1000
Jack Johnson, ${'$'}1000
James Johnson, ${'$'}1000
Jon Johnson, ${'$'}1000
Naja Marcson, ${'$'}5000
Alex Nolan, ${'$'}1000
Ron Peters, ${'$'}3000
Marc Smith, ${'$'}3000
""".trimIndent()
assertEquals(expected, text)
}
}
