[JAVA] Implement FizzBuzz problem in test-driven development (preparation)

First of all, I would like to write test code ... but before that, I need to make sure that JUnit is installed correctly.

Specifically, prepare the test class FizzBuzzTest.java, write an empty test program, and execute the test.

Creating FizzBuzzTest.java

First, prepare the test class according to the following procedure.

1. Place the cursor on "src / __ test__ / java", right-click-> New-> Package
2. Enter any package name in the Name field and click Finish
3. Place the cursor on the created package, right-click-> click Class
4. Enter FizzBuzzTest in the Name field and click Finish (other settings are left at their defaults)

The project structure after creating FizzBuzzTest.java is as follows.

Create an empty test program

Next, implement an empty test method that does nothing in the created FizzBuzzTest.java.

FizzBuzzTest.java

import org.junit.Test;

public class FizzBuzzTest {
    @Test
public void JUnit operation test() {
        
    }
}

Test run

Hover over the JUnit behavior test method of the FizzBuzzTest class you created and right-click-> Run As-> JUnit Test to run the test.

Then you will see a green bar indicating that the test was successful, as shown in the figure below.

From this, you can see that JUnit is working as default and you are ready to use JUnit. On the other hand, if the test fails, you can discover flaws in the test environment, such as improper installation by Maven.

Now that you've confirmed that JUnit works, you're done with ** Preparation **.

Here, the final project structure and program contents are listed as "Conclusion comes first". [^ 3]

Project structure

Test program

FizzBuzzTest.java

package com.example;

import static org.junit.Assert.assertEquals;

import org.junit.Test;
import org.junit.experimental.runners.Enclosed;
import org.junit.runner.RunWith;

@RunWith(Enclosed.class)
public class FizzBuzzTest {

public static class argument is not a multiple of 3 and 5{
        FizzBuzz fizzbuzz = new FizzBuzz();

        @Test
public void Returns 1 if 1 is given as an argument() {
            assertEquals("1", fizzbuzz.response(1));
        }
    }
    
public static class A multiple of 3 arguments only{
        FizzBuzz fizzbuzz = new FizzBuzz();

        @Test
public void Returns Fizz with argument 3() {
            assertEquals("Fizz", fizzbuzz.response(3));
        }
    }

public static class A multiple of 5 arguments only{
        FizzBuzz fizzbuzz = new FizzBuzz();

        @Test
public void Returns Buzz with argument 5() {
            assertEquals("Buzz", fizzbuzz.response(5));
        }
    }

public static class arguments are multiples of 3 and 5{
        FizzBuzz fizzbuzz = new FizzBuzz();

        @Test
public void Returns FizzBuzz with argument 15() {
            assertEquals("FizzBuzz", fizzbuzz.response(15));
        }
    }
    
public static class argument is a valid boundary value{
        FizzBuzz fizzbuzz = new FizzBuzz();
        
        @Test
public void Returns 1 if argument 1 is given() {
            assertEquals("1", fizzbuzz.response(1));
        }

        @Test
public void Returns Buzz with 100 arguments() {
            assertEquals("Buzz", fizzbuzz.response(100));
        }
    }

public static class argument is invalid Boundary value{
        FizzBuzz fizzbuzz = new FizzBuzz();
        
        @Test(expected = IndexOutOfBoundsException.class)
public void error occurs if argument 0 is given() {
            fizzbuzz.response(0);
        }

        @Test(expected = IndexOutOfBoundsException.class)
public void error occurs if argument 101 is given() {
            fizzbuzz.response(101);
        }
    }
}

Program to be tested

FizzBuzz.java

public class FizzBuzz {

    public String response(int num) {
        StringBuilder result = new StringBuilder();
        
        if(num < 1 || num > 100) {
            throw new IndexOutOfBoundsException();
        }
        
        if(num % 3 == 0) {
            result.append("Fizz");
        }

        if(num % 5 == 0) {
            result.append("Buzz");
        }
        
        if(result.length() == 0) {
            result.append(String.valueOf(num));
        }

        return result.toString();
    }
}

Next time, I would like to post as ** Practice ** how I proceeded with the implementation of the following test class (FizzBuzzTest.java) and test target class (FizzBuzz.java).

reference

• [Amazon \ .co \ .jp: [Understanding in this one book] Software test textbook-Basics and practice of the test process that determines quality eBook: Kazuhiro Ishihara, Hidekazu Tanaka, Masashi Tanaka: Kindle Store](https:: //www.amazon.co.jp/%E3%80%90%E3%81%93%E3%81%AE1%E5%86%8A%E3%81%A7%E3%82%88%E3%81 % 8F% E3% 82% 8F% E3% 81% 8B% E3% 82% 8B% E3% 80% 91% E3% 82% BD% E3% 83% 95% E3% 83% 88% E3% 82% A6 % E3% 82% A7% E3% 82% A2% E3% 83% 86% E3% 82% B9% E3% 83% 88% E3% 81% AE% E6% 95% 99% E7% A7% 91% E6 % 9B% B8_% E5% 93% 81% E8% B3% AA% E3% 82% 92% E6% B1% BA% E5% AE% 9A% E3% 81% A5% E3% 81% 91% E3% 82 % 8B% E3% 83% 86% E3% 82% B9% E3% 83% 88% E5% B7% A5% E7% A8% 8B% E3% 81% AE% E5% 9F% BA% E6% 9C% AC % E3% 81% A8% E5% AE% 9F% E8% B7% B5-% E7% 9F% B3% E5% 8E% 9F-% E4% B8% 80% E5% AE% 8F-ebook / dp / B00U17809A / ref = sr_1_1? ie = UTF8 & qid = 1496770784 & sr = 8-1 & keywords =% E3% 82% BD% E3% 83% 95% E3% 83% 88% E3% 82% A6% E3% 82% A7% E3% 82% A2% E3% 83% 86% E3% 82% B9% E3% 83% 88% E3% 81% AE% E6% 95% 99% E7% A7% 91% E6% 9B% B8)

• Read "Why most unit tests don't help"|Development method / project management| POSTD

• Test Driven Development in 50 Minutes / TDD Live in 50 minutes // Speaker Deck

• What is Test Driven Development, Why Do You Like It, Why You Should Use It|Development method / project management| POSTD

• What is the Fizz \ -Buzz problem? -Hatena keyword

[^ 1]: I only read the summary, but the original story is [Why \ -Most \ -Unit \ -Testing \ -is \ -Waste \ .pdf](http://rbcs-us.com/ documents / Why-Most-Unit-Testing-is-Waste.pdf) It is written in.

[^ 2]: For example, in a movie reservation system that has multiple discount options according to user characteristics, if the final requirement is "apply the option that increases the discount rate", then from the user characteristic condition that the discount rate is high I will test it.

[^ 3]: There are some differences from the live coding in de: code that I referred to because it was the result of my own practice and some parts were omitted in de: code due to time constraints.