tddyyχ_2018-03-31

FizzBuzz.java

public class FizzBuzz {

    public static String answer(int number) {

        if (number % 15 == 0 ) {
            return "FizzBuzz";
        } else if (number % 3 == 0 ) {
            return "Fizz";
        } else if (number % 5 == 0) {
            return "Buzz";
        }
        
        return String.valueOf(number);
    }
    
    public static void print(String text) {
        System.out.println(text);
    }

    public static void spike(int number) {
        for (int i = 1; i <= number; i++) {
            print(answer(i));
        }
    }
}

FizzBuzzTest.java

import org.junit.*;
import static org.junit.Assert.*;
import java.io.*;

public class FizzBuzzTest {
    private ByteArrayOutputStream _baos;
    private PrintStream _out;

    @Before public void setUp() {
        _baos = new ByteArrayOutputStream();
        _out = System.out;
        System.setOut(
            new PrintStream(
                new BufferedOutputStream(_baos)
            )
        );
    }

    @After public void tearDown() {
        System.setOut(_out);
    }

    @Test
    public void _3の時にFizzが返る() {
        String expected = "Fizz";
        String actual = FizzBuzz.answer(3);
        assertEquals(expected, actual);
    }
    
    @Test
    public void _6の時にFizzが返る() {
        String expected = "Fizz";
        String actual = FizzBuzz.answer(6);
        assertEquals(expected, actual);
    }
    
    @Test
    public void _5の時にBuzzが返る() {
        String expected = "Buzz";
        String actual = FizzBuzz.answer(5);
        assertEquals(expected, actual);
    }

    @Test
    public void _10の時にBuzzが返る() {
        String expected = "Buzz";
        String actual = FizzBuzz.answer(10);
        assertEquals(expected, actual);
    }

    @Test
    public void _1のとき文字列の1が返る() {
        String expected = "1";
        String actual = FizzBuzz.answer(1);
        assertEquals(expected, actual);
    }
    
    @Test
    public void _2のとき文字列の2が返る() {
        String expected = "2";
        String actual = FizzBuzz.answer(2);
        assertEquals(expected, actual);
    }
    
    @Test
    public void _15の時にFizzBuzzが返る() {
        String expected = "FizzBuzz";
        String actual = FizzBuzz.answer(15);
        assertEquals(expected, actual);
    }
    
    @Test
    public void _与えられた文字列を出力する() {
        FizzBuzz.print("Buzz");
        System.out.flush();
        String expected = "Buzz\n";
        String actual = _baos.toString();
        
        assertEquals(expected, actual);
    }    
    
    @Test
    public void _1から渡された数までFizzBuzzにわたすとよきように文字列を出力する() {
        FizzBuzz.spike(4);
        System.out.flush();
        String expected = "1\n2\nFizz\n4\n";
        String actual = _baos.toString();
        
        assertEquals(expected, actual);
    }
}