Solution: User Information Processor
fun processUserInformation(user: User?): String {
if (user == null) {
return "Missing user information"
}
val name = requireNotNull(user.name)
val age = user.age ?: 0
val email = user.email?.email
if (email.isNullOrBlank()) {
return "Missing email"
}
return "User $name is $age years old, email: $email"
}
Example solution in playground
import org.junit.Assert.assertThrows
import org.junit.Test
import kotlin.test.assertEquals
fun processUserInformation(user: User?): String {
if (user == null) {
return "Missing user information"
}
val name = requireNotNull(user.name)
val age = user.age ?: 0
val email = user.email?.email
if (email.isNullOrBlank()) {
return "Missing email"
}
return "User $name is $age years old, email: $email"
}
data class EmailAddress(val email: String?)
data class User(
val name: String?,
val age: Int?,
val email: EmailAddress?
)
fun main() {
println(processUserInformation(null))
// Missing user information
val user1 = User(
"John",
30,
EmailAddress("john@example.com")
)
println(processUserInformation(user1))
// User John is 30 years old, email: john@example.com
val user2 = User(
"Alice",
null,
EmailAddress("alice@example.com")
)
println(processUserInformation(user2))
// User Alice is 0 years old, email: alice@example.com
val user3 = User(
"Bob",
25,
EmailAddress("") // or EmailAddress(null) or null
)
println(processUserInformation(user3))
// Missing email
val user6 = User(
null,
40,
EmailAddress("jake@example.com")
)
println(processUserInformation(user6))
// IllegalArgumentException
}
class StudentInformationTest {
@Test
fun `valid user information`() {
val user = User("John Doe", 30, EmailAddress("john@example.com"))
val result = processUserInformation(user)
val expected = "User John Doe is 30 years old, email: john@example.com"
assertEquals(expected, result)
}
@Test
fun `null user information`() {
val result = processUserInformation(null)
val expected = "Missing user information"
assertEquals(expected, result)
}
@Test
fun `user with missing age should have age 0`() {
val user = User("Alice", null, EmailAddress("alice@example.com"))
val result = processUserInformation(user)
val expected = "User Alice is 0 years old, email: alice@example.com"
assertEquals(expected, result)
}
@Test
fun `user with blank email`() {
val user = User("Bob", 25, EmailAddress(""))
val result = processUserInformation(user)
val expected = "Missing email"
assertEquals(expected, result)
}
@Test
fun `user with null email address`() {
val user = User("Bob", 25, EmailAddress(null))
val result = processUserInformation(user)
val expected = "Missing email"
assertEquals(expected, result)
}
@Test
fun `user with null email information`() {
val user = User("Bob", 25, null)
val result = processUserInformation(user)
val expected = "Missing email"
assertEquals(expected, result)
}
@Test
fun `user with missing name should throw exception`() {
val user = User(null, 40, EmailAddress("email@example.com"))
assertThrows(IllegalArgumentException::class.java) {
processUserInformation(user)
}
}
}
