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to Gigasecond in the Scala Track

Published at Oct 10 2019 · 0 comments
Test suite

Given a moment, determine the moment that would be after a gigasecond has passed.

A gigasecond is 10^9 (1,000,000,000) seconds.


Note that addGigaseconds accepts two different types of input.

The Scala exercises assume an SBT project scheme. The exercise solution source should be placed within the exercise directory/src/main/scala. The exercise unit tests can be found within the exercise directory/src/test/scala.

To run the tests simply run the command sbt test in the exercise directory.

Please see the learning and installation pages if you need any help.


Chapter 9 in Chris Pine's online Learn to Program tutorial. http://pine.fm/LearnToProgram/?Chapter=09

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


import java.time.LocalDate
import java.time.LocalDateTime
import java.time.format.DateTimeFormatter

import org.scalatest.{Matchers, FunSuite}

/** @version 1.1.0 */
class GigasecondTest extends FunSuite with Matchers {

  private def dateTime(str: String): LocalDateTime =
  private def date(str: String): LocalDate =

  test("date only specification of time") {
    val input = date("2011-04-25")
    val expected = dateTime("2043-01-01T01:46:40")
    Gigasecond.add(input) should be (expected)

  test("second test for date only specification of time") {
    val input = date("1977-06-13")
    val expected = dateTime("2009-02-19T01:46:40")
    Gigasecond.add(input) should be (expected)

  test("third test for date only specification of time") {
    val input = date("1959-07-19")
    val expected = dateTime("1991-03-27T01:46:40")
    Gigasecond.add(input) should be (expected)

  test("full time specified") {
    val input = dateTime("2015-01-24T22:00:00")
    val expected = dateTime("2046-10-02T23:46:40")
    Gigasecond.add(input) should be (expected)

  test("full time with day roll-over") {
    val input = dateTime("2015-01-24T23:59:59")
    val expected = dateTime("2046-10-03T01:46:39")
    Gigasecond.add(input) should be (expected)
import java.time.LocalDate
import java.time.LocalDateTime

object Gigasecond {
  def add(startDate: LocalDate): LocalDateTime = add(startDate.atStartOfDay())

  def add(startDateTime: LocalDateTime): LocalDateTime = startDateTime.plusSeconds(1000000000)

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SirHC77's Reflection

As a maintenance aside, folks should consider making the LocalDate function use the LocalDateTime function, instead of having that constant value twice in their code. I should have considered having the constant as its own private value, but... meh... :-)