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 {

    @Test
    void testCustomerCountIncremented() {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        PrintStream original = System.out;
        System.setOut(new PrintStream(out));

        Main.printShopReport();

        System.setOut(original);
        String output = out.toString().trim().toLowerCase();

        assertTrue(output.contains("6"),
            "Customer count should be 6 after increment. Got: " + output);
    }

    @Test
    void testTotalEarnings() {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        PrintStream original = System.out;
        System.setOut(new PrintStream(out));

        Main.printShopReport();

        System.setOut(original);
        String output = out.toString().trim().toLowerCase();

        assertTrue(output.contains("108.0"),
            "Total earnings should be 108.0. Got: " + output);
    }

    @Test
    void testOutputContainsLabels() {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        PrintStream original = System.out;
        System.setOut(new PrintStream(out));

        Main.printShopReport();

        System.setOut(original);
        String output = out.toString().trim().toLowerCase();

        assertTrue(output.contains("total number of customers"),
            "Output should contain 'Total number of customers'. Got: " + output);
        assertTrue(output.contains("total earnings"),
            "Output should contain 'Total earnings'. 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: Calculating Coffee Shop Revenue

Solution