start exam implementation: with the notate method, driven by test #5
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…ation, not the exam. Start the refactoring
…project is not officilay supported in intellij today, job must be done manually)
…is. Some issues remains with junit 5, spring integration and kotlin
| import java.math.BigDecimal | ||
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| data class Exam(val id: Long) { | ||
| fun validateNotation(notation: BigDecimal): Either<InvalidNotationForThisExamException, Unit> = |
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In English, this would be a grade :)
| fun validateNotation(notation: BigDecimal): Either<InvalidNotationForThisExamException, Unit> = | ||
| when (notation) { | ||
| in (0.toBigDecimal()..20.toBigDecimal()) -> Either.right(Unit) | ||
| else -> Either.left(InvalidNotationForThisExamException("This notation, $notation, is not in bound")) |
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I'd probably call it a GradeOutOfBoundsException
| } | ||
| } | ||
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| class InvalidNotationForThisExamException(msg: String?) : RuntimeException(msg) |
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Kotlin exceptions are unchecked, so simply Exception is sufficient unless cross-compatibility with Java is required.
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| } | ||
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| class NotEvaluatedException(msg: String? = null, throwable: Throwable? = null) : RuntimeException(msg, throwable) |
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A default message is probably preferable to null, yes?
| else -> Either.left(NotEvaluatedException()) | ||
| } | ||
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| fun notate(exam: Exam, note: BigDecimal): Either<InvalidNotationForThisExamException, Student> = |
| studentsRepository.findStudentById(studentId = 1).flatMap { student -> | ||
| examsRepository.findExamById(examId = notateExam.examId).flatMap { exam -> | ||
| student.notate(exam, notateExam.note).flatMap { updatedStudent -> | ||
| studentsRepository.save(updatedStudent) |
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There are too many levels of abstraction here and it is not clear what this method is doing. Remember the SRP :)
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What would you remove there is only two call and entity method.
Maybe you do not like flatMap with either, but I don't see how to do it shorter than that
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Maybe by giving up either, but I want to use it to handle errors
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Mostly that we jump from a student into an exam into a grade for that exam and student. all the while nesting. Exam doesn't depend on student, so the nesting is odd.
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Nesting helps to get the values directly. The other solution is to do if(isRight()=> toOption().get()) etc..etc but I really don't like that solution (I tested it)
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I searched a lot, and normally the following code is better and compile (I need to check at home)
notateExam.also {
ForEither<RepositoryException>() extensions {
tupled(
studentsRepository.findStudentById(studentId),
examsRepository.findExamById(examId)
)
}.flatMap { (student, exam) ->
student.notate(exam, note).flatMap { studentsRepository.save(it) }
}.mapLeft { NotateExamException(throwable = it) }
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It does not work, please close it, it is useless
| class StudentsInteractor(private val studentsRepository: StudentsRepository, private val examsRepository: ExamsRepository) : Students { | ||
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| override fun notate(notateExam: NotateExam): Either<NotateExamException, Unit> = | ||
| studentsRepository.findStudentById(studentId = 1).flatMap { student -> |
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your studentId is defined in the notateExam class, we should probably use that otherwise your student 1 will get all the grades
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I already noticed it in my comment, but thx
| val studentsInteractor = StudentsInteractor(studentRepository, examsRepository) | ||
| studentsInteractor.notate20().apply { | ||
| it("should notate an existing exam with a note of 20") { | ||
| isRight() `should be` true |
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The actual grade isn't checked here. How do we know it's 20?
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Yes this test should be deleted because check is done in the last test
| typealias Grades = Map<Exam, Grade> | ||
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| data class Student(val id: Long, val grades: Grades = emptyMap()) { | ||
| fun getNotation(exam: Exam): Either<NotEvaluatedException, BigDecimal> = |
| else -> Either.left(NotEvaluatedException()) | ||
| } | ||
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| fun notate(exam: Exam, note: BigDecimal): Either<InvalidNotationForThisExamException, Student> = |
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Oops should be grade not notate
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And a Grade not a BigDecimal
| it("should retrieve exam by id") { | ||
| verify { examsRepository.findExamById(5) } | ||
| } | ||
| it("should save student to the repository with the expected notation of 20 for this exam") { |
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