世界のナベアツ版FizzBuzz問題

デブサミ

今日の笑いのレッドカーペットでFizzBuzz問題とそっくりなネタを「世界のナベアツ」がやっていたので、それでFizzBuzzを解いてみた。id:t-wadaさんの「デベロッパーテスティング・ライブ」で見たJUnit4.4も使ってみました。

Wikipedia:世界のナベアツ

「世界のナベアツ版FizzBuzz問題のルール」

３の倍数と３のつく数字であほになって、５の倍数で犬になる。

追記：
id:t-wadaさんのコメントを受けてテストを修正しました。
以前のassertEqualsに慣れていると、うっかり間違えちゃいますね。JUnit4.4流の書き方でしばらく書いてみて慣れていってみようと思います。

assertThatでは、(英語として読めるように意図しているため)期待値と実際値の順番が逆になります。
ですから、
assertThat(”1”, is(fizzBuzz.fizzBuzz(1)));
ではなくて
assertThat(fizzBuzz.fizzBuzz(1), is(”1”));


FizzBuzzTest.java

package jp.co.nulab.sekainonabeatsu;

import java.io.StringWriter;

import junit.framework.TestCase;

import org.junit.Test;

import static org.junit.Assert.assertThat;

import static org.hamcrest.core.Is.is;

public class FizzBuzzTest extends TestCase {

	@Test
	public void testFuzzBuzz() {
		FizzBuzz fizzBuzz = new FizzBuzz(new StringWriter());
		assertThat(fizzBuzz.fizzBuzz(1), is("1"));
		assertThat(fizzBuzz.fizzBuzz(2), is("2"));
		assertThat(fizzBuzz.fizzBuzz(3), is("3(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(4), is("4"));
		assertThat(fizzBuzz.fizzBuzz(5), is("5U^ェ^U"));
		assertThat(fizzBuzz.fizzBuzz(6), is("6(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(7), is("7"));
		assertThat(fizzBuzz.fizzBuzz(8), is("8"));
		assertThat(fizzBuzz.fizzBuzz(9), is("9(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(10), is("10U^ェ^U"));

		assertThat(fizzBuzz.fizzBuzz(11), is("11"));
		assertThat(fizzBuzz.fizzBuzz(12), is("12(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(13), is("13(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(14), is("14"));
		assertThat(fizzBuzz.fizzBuzz(15), is("15(￣o￣)ア(￣O￣)ホッ！U^ェ^U"));
		assertThat(fizzBuzz.fizzBuzz(16), is("16"));
		assertThat(fizzBuzz.fizzBuzz(17), is("17"));
		assertThat(fizzBuzz.fizzBuzz(18), is("18(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(19), is("19"));
		assertThat(fizzBuzz.fizzBuzz(20), is("20U^ェ^U"));

		assertThat(fizzBuzz.fizzBuzz(21), is("21(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(22), is("22"));
		assertThat(fizzBuzz.fizzBuzz(23), is("23(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(24), is("24(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(25), is("25U^ェ^U"));
		assertThat(fizzBuzz.fizzBuzz(26), is("26"));
		assertThat(fizzBuzz.fizzBuzz(27), is("27(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(28), is("28"));
		assertThat(fizzBuzz.fizzBuzz(29), is("29"));
		assertThat(fizzBuzz.fizzBuzz(30), is("30(￣o￣)ア(￣O￣)ホッ！U^ェ^U"));

		assertThat(fizzBuzz.fizzBuzz(31), is("31(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(32), is("32(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(33), is("33(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(34), is("34(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(35), is("35(￣o￣)ア(￣O￣)ホッ！U^ェ^U"));
		assertThat(fizzBuzz.fizzBuzz(36), is("36(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(37), is("37(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(38), is("38(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(39), is("39(￣o￣)ア(￣O￣)ホッ！"));
		assertThat(fizzBuzz.fizzBuzz(40), is("40U^ェ^U"));
	}

	@Test
	public void 全パターンの出力() {
		// 標準出力の場合 new OutputStreamWriter(System.out);
		StringWriter out = new StringWriter();
		FizzBuzz fizzBuzz = new FizzBuzz(out);
		fizzBuzz.fizzBuzzAll();
		String expected = "1\n2\n3(￣o￣)ア(￣O￣)ホッ！\n4\n5U^ェ^U\n6(￣o￣)ア(￣O￣)ホッ！\n7\n8\n9(￣o￣)ア(￣O￣)ホッ！\n10U^ェ^U\n11\n" +
				"12(￣o￣)ア(￣O￣)ホッ！\n13(￣o￣)ア(￣O￣)ホッ！\n14\n15(￣o￣)ア(￣O￣)ホッ！U^ェ^U\n16\n17\n18(￣o￣)ア(￣O￣)ホッ！\n19\n20U^ェ^U\n" +
				"21(￣o￣)ア(￣O￣)ホッ！\n22\n23(￣o￣)ア(￣O￣)ホッ！\n24(￣o￣)ア(￣O￣)ホッ！\n25U^ェ^U\n26\n27(￣o￣)ア(￣O￣)ホッ！\n28\n29\n30(￣o￣)ア(￣O￣)ホッ！U^ェ^U\n" +
				"31(￣o￣)ア(￣O￣)ホッ！\n32(￣o￣)ア(￣O￣)ホッ！\n33(￣o￣)ア(￣O￣)ホッ！\n34(￣o￣)ア(￣O￣)ホッ！\n35(￣o￣)ア(￣O￣)ホッ！U^ェ^U\n36(￣o￣)ア(￣O￣)ホッ！\n37(￣o￣)ア(￣O￣)ホッ！\n38(￣o￣)ア(￣O￣)ホッ！\n39(￣o￣)ア(￣O￣)ホッ！\n40U^ェ^U\n";
		assertThat(out.toString(), is(expected));
	}
}


FizzBuzz.java

package jp.co.nulab.sekainonabeatsu;

import java.io.IOException;
import java.io.Writer;


public class FizzBuzz {

	private final Writer out;

	public FizzBuzz(Writer out) {
		this.out = out;
	}

	public String fizzBuzz(int no) {
		String noStr = String.valueOf(no);
		StringBuilder sb = new StringBuilder();
		sb.append(noStr);
		if (no % 3 == 0 || noStr.contains("3")) {
			sb.append("(￣o￣)ア(￣O￣)ホッ！");
		}
		if (no % 5 == 0) {
			sb.append("U^ェ^U");
		}
		return sb.toString();
	}

	public void fizzBuzzAll() {
		for (int i = 1; i < 41; i++) {
			try {
				this.out.append(fizzBuzz(i));
				this.out.append("\n");
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
	}
}