dtonhofer

dtonhofer

Functional Programming in Java, Second Edition: Functional Programming in Java, Second Edition: JUnit code improvements for Chapter 11, pages 184 ff “Refactoring More Complex loops”

The same remarks apply as for “Refactoring the Traditional for Loop”

  • No init()
  • Classes under test implement a common interface that is called in tests.
  • Negative tests which apply for input less than 1900, resulting in exceptions.
package chapter11;

import org.junit.jupiter.api.Test;

import java.time.Year;
import java.util.stream.IntStream;

import static org.junit.jupiter.api.Assertions.*;

// Everything is inside the MoreComplexLoopTest class for convenience.
// Documentation for java.time.Year.isLeap()
// https://docs.oracle.com/javase/8/docs/api/java/time/Year.html#isLeap--

public class MoreComplexLoopTest {

    interface LeapYears {

        int countFrom1900(int upTo);

    }

    static class LeapYearCountBefore implements LeapYears {

        public int countFrom1900(int upTo) {
            if (upTo < 1900) {
                throw new IllegalArgumentException("The passed value is < 1900: " + upTo);
            }
            int count = 0;
            for (int year = 1900; year <= upTo; year += 4) {
                if (Year.isLeap(year)) {
                    count++;
                }
            }
            return count;
        }

    }

    static class LeapYearCountAfter implements LeapYears {

        public int countFrom1900(int upTo) {
            if (upTo < 1900) {
                throw new IllegalArgumentException("The passed value is < 1900: " + upTo);
            }
            return (int) IntStream.iterate(1900, year -> year <= upTo, year -> year + 4)
                    .filter(Year::isLeap)
                    .count();
        }

    }

    private static void commonLeapYearsTests(final LeapYears leapYears) {
        assertAll(
                () -> assertEquals(0, leapYears.countFrom1900(1900)),
                () -> assertEquals(25, leapYears.countFrom1900(2000)),
                () -> assertEquals(27, leapYears.countFrom1900(2010)),
                () -> assertEquals(31, leapYears.countFrom1900(2025)),
                () -> assertEquals(49, leapYears.countFrom1900(2100)),
                () -> assertEquals(267, leapYears.countFrom1900(3000)),
                () -> assertThrows(IllegalArgumentException.class, () -> leapYears.countFrom1900(1800))
        );
    }

    @Test
    void leapYearCountBefore() {
        commonLeapYearsTests(new LeapYearCountBefore());
    }

    @Test
    void leapYearCountAfter() {
        commonLeapYearsTests(new LeapYearCountAfter());
    }

}

Where Next?

Popular Pragmatic Bookshelf topics Top

telemachus
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
New
curtosis
Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
New
fynn
This is as much a suggestion as a question, as a note for others. Locally the SGP30 wasn’t available, so I ordered a SGP40. On page 53, ...
New
jskubick
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
brunogirin
When running tox for the first time, I got the following error: ERROR: InterpreterNotFound: python3.10 I realised that I was running ...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
creminology
Skimming ahead, much of the following is explained in Chapter 3, but new readers (like me!) will hit a roadblock in Chapter 2 with their ...
New
jwandekoken
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
New
dtonhofer
@parrt In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
New
davetron5000
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New

Other popular topics Top

ohm
Which, if any, games do you play? On what platform? I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
Exadra37
Please tell us what is your preferred monitor setup for programming(not gaming) and why you have chosen it. Does your monitor have eye p...
New
AstonJ
There’s a whole world of custom keycaps out there that I didn’t know existed! Check out all of our Keycaps threads here: https://forum....
New
rustkas
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
AstonJ
We’ve talked about his book briefly here but it is quickly becoming obsolete - so he’s decided to create a series of 7 podcasts, the firs...
New
AstonJ
If you get Can't find emacs in your PATH when trying to install Doom Emacs on your Mac you… just… need to install Emacs first! :lol: bre...
New
PragmaticBookshelf
Author Spotlight Jamis Buck @jamis This month, we have the pleasure of spotlighting author Jamis Buck, who has written Mazes for Prog...
New
PragmaticBookshelf
Get the comprehensive, insider information you need for Rails 8 with the new edition of this award-winning classic. Sam Ruby @rubys ...
New
PragmaticBookshelf
Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...
New
RobertRichards
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
New

Latest in Functional Programming in Java, Second Edition

Functional Programming in Java, Second Edition Portal

Sub Categories: