package com.example;

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

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.util.regex.Pattern;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

public class MainTest {
    @Test
    @DisplayName("printWelcome prints correct welcome message")
    void testPrintWelcome() {
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        PrintStream originalOut = System.out;
        System.setOut(new PrintStream(outContent));

        Main.printWelcome();

        System.setOut(originalOut);
        String output = outContent.toString().trim();
        Pattern pattern = Pattern.compile(
            "welcome\\\\s+to\\\\s+the\\\\s+java\\\\s+methods\\\\s+challenge!",
            Pattern.CASE_INSENSITIVE
        );
        assertTrue(pattern.matcher(output).find(), "Expected welcome message, got: '" + output + "'");
    }

    @Test
    @DisplayName("showInstructions prints correct instruction message")
    void testShowInstructions() {
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        PrintStream originalOut = System.out;
        System.setOut(new PrintStream(outContent));

        Main.showInstructions();

        System.setOut(originalOut);
        String output = outContent.toString().trim();
        Pattern pattern = Pattern.compile(
            "follow\\\\s+the\\\\s+instructions\\\\s+carefully\\\\s+to\\\\s+complete\\\\s+the\\\\s+task\\\\s*\\\\.",
            Pattern.CASE_INSENSITIVE
        );
        assertTrue(pattern.matcher(output).find(), "Expected instructions message, got: '" + output + "'");
    }

    @Test
    @DisplayName("printCompletion prints correct completion message")
    void testPrintCompletion() {
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        PrintStream originalOut = System.out;
        System.setOut(new PrintStream(outContent));

        Main.printCompletion();

        System.setOut(originalOut);
        String output = outContent.toString().trim();
        Pattern pattern = Pattern.compile(
            "congratulations!\\\\s+you\\\\s+have\\\\s+completed\\\\s+the\\\\s+challenge\\\\s*\\\\.",
            Pattern.CASE_INSENSITIVE
        );
        assertTrue(pattern.matcher(output).find(), "Expected completion message, got: '" + output + "'");
    }

    @Test
    @DisplayName("main prints all messages in order")
    void testMainAllMessages() {
        ByteArrayOutputStream outContent = new ByteArrayOutputStream();
        PrintStream originalOut = System.out;
        System.setOut(new PrintStream(outContent));

        Main.main(new String[]{});

        System.setOut(originalOut);
        String output = outContent.toString().toLowerCase();
        int idxWelcome = output.indexOf("welcome to the java methods challenge!");
        int idxInstructions = output.indexOf("follow the instructions carefully to complete the task.");
        int idxCompletion = output.indexOf("congratulations! you have completed the challenge.");
        assertTrue(idxWelcome != -1, "Welcome message missing");
        assertTrue(idxInstructions != -1, "Instructions message missing");
        assertTrue(idxCompletion != -1, "Completion message missing");
        assertTrue(idxWelcome < idxInstructions && idxInstructions < idxCompletion,
            "Messages are not printed in the correct order");
    }
}

MainTest.java

A comprehensive course dedicated to understanding, designing, and applying methods in Java. Explore method fundamentals, parameter passing, overloading, recursion, and best practices through a blend of theory and hands-on coding challenges.

Explore the basics of methods in Java, including their structure, purpose, and how they enable code reuse and modularity.

Delve into parameter passing, argument types, and how methods interact with data.

Explore method overloading, recursion, and best practices for designing effective methods.

Challenge: Basic Method Creation

Lösning

Challenge: Basic Method Creation

Lösning