package com.example;

import org.junit.jupiter.api.Test;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import static org.junit.jupiter.api.Assertions.*;

public class MainTest {

    private String captureOutput() {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        PrintStream original = System.out;
        System.setOut(new PrintStream(out));
        Main.showBagWeight();
        System.setOut(original);
        return out.toString().trim();
    }

    @Test
    void testDoubleWeightOutput() {
        String output = captureOutput();
        assertTrue(output.contains("760.5"),
            "Output should contain updated double weight 760.5. Got: " + output);
    }

    @Test
    void testIntReportedWeightOutput() {
        String output = captureOutput();
        assertTrue(output.contains("760"),
            "Output should contain reported int weight 760. Got: " + output);
    }

    @Test
    void testOutputLabels() {
        String output = captureOutput().toLowerCase();
        assertTrue(output.contains("updated bag weight (double)"),
            "Output should contain label 'Updated bag weight (double)'. Got: " + output);
        assertTrue(output.contains("final reported weight (int)"),
            "Output should contain label 'Final reported weight (int)'. Got: " + output);
    }
    
    @Test
    void testTruncationNotRounding() {
        String output = captureOutput();
        assertTrue(output.contains("760") && !output.contains("761"),
            "Explicit cast should truncate 760.5 to 760, not round to 761. Got: " + output);
    }
}

MainTest.java

Dive into the fundamentals of Java by learning the core concepts that power modern applications. Explore variables, data types, operators, conditionals, and strings while building a strong foundation in programming. Through practical examples and hands-on challenges, you'll develop the skills needed to write, understand, and troubleshoot Java code with confidence.

Discover how to begin your Java journey by learning what Java is, where it is used, and how Java programs are structured. Understand how to print output, write comments, and build the foundation needed for all future programming concepts.

Master the skills needed to store, manage, and work with data in Java. Learn how variables, constants, data types, operators, and type casting work, and apply these concepts through practical coding exercises and real-world examples.

Explore the essentials of decision-making in Java by working with comparison and logical operators, conditional statements, and switch expressions. Learn how programs evaluate conditions, make choices, and respond to different situations through practical examples and challenges.

Dive into the fundamentals of working with text in Java. Learn how strings are created and manipulated, explore formatting and comparison techniques, validate user input, extract useful information from text, and apply these skills in realistic programming scenarios.

Challenge: Coffee Bag Weight Conversion

Solution