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artemkorsakov's solution

to Space Age in the Java Track

Published at Jan 29 2019 · 0 comments
Test suite


This exercise has changed since this solution was written.

Given an age in seconds, calculate how old someone would be on:

  • Earth: orbital period 365.25 Earth days, or 31557600 seconds
  • Mercury: orbital period 0.2408467 Earth years
  • Venus: orbital period 0.61519726 Earth years
  • Mars: orbital period 1.8808158 Earth years
  • Jupiter: orbital period 11.862615 Earth years
  • Saturn: orbital period 29.447498 Earth years
  • Uranus: orbital period 84.016846 Earth years
  • Neptune: orbital period 164.79132 Earth years

So if you were told someone were 1,000,000,000 seconds old, you should be able to say that they're 31.69 Earth-years old.

If you're wondering why Pluto didn't make the cut, go watch this youtube video.

Running the tests

You can run all the tests for an exercise by entering

$ gradle test

in your terminal.


Partially inspired by Chapter 1 in Chris Pine's online Learn to Program tutorial. http://pine.fm/LearnToProgram/?Chapter=01

Submitting Incomplete Solutions

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


import org.junit.Test;
import org.junit.Ignore;

import static org.junit.Assert.assertEquals;

public class SpaceAgeTest {

    private static final double MAXIMUM_DELTA = 1E-02;

    public void ageOnEarth() {
        SpaceAge age = new SpaceAge(1000000000);

        assertEquals(31.69, age.onEarth(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnMercury() {
        SpaceAge age = new SpaceAge(2134835688);

        assertEquals(280.88, age.onMercury(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnVenus() {
        SpaceAge age = new SpaceAge(189839836);

        assertEquals(9.78, age.onVenus(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnMars() {
        SpaceAge age = new SpaceAge(2329871239L);

        assertEquals(39.25, age.onMars(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnJupiter() {
        SpaceAge age = new SpaceAge(901876382);

        assertEquals(2.41, age.onJupiter(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnSaturn() {
        SpaceAge age = new SpaceAge(3000000000L);

        assertEquals(3.23, age.onSaturn(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnUranus() {
        SpaceAge age = new SpaceAge(3210123456L);

        assertEquals(1.21, age.onUranus(), MAXIMUM_DELTA);

    @Ignore("Remove to run test")
    public void ageOnNeptune() {
        SpaceAge age = new SpaceAge(8210123456L);

        assertEquals(1.58, age.onNeptune(), MAXIMUM_DELTA);
class SpaceAge {
    private double seconds;

    SpaceAge(double seconds) {
        this.seconds = seconds;

    double getSeconds() {
        return seconds;

    double onEarth() {
        return seconds / 31557600;

    double onMercury() {
        return onEarth() / 0.2408467;

    double onVenus() {
        return onEarth() / 0.61519726;

    double onMars() {
        return onEarth() / 1.8808158;

    double onJupiter() {
        return onEarth() / 11.862615;

    double onSaturn() {
        return onEarth() / 29.447498;

    double onUranus() {
        return onEarth() / 84.016846;

    double onNeptune() {
        return onEarth() / 164.79132;


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