Randori Arab to romans @ Key Consulting 13/12/2011

Converter.java

public class Converter {
	public static String toRomans(int i) {
		return getMultipleM(i/1000) + toRomans(i/100,"C","D","M") + toRomans(i/10, "X", "L", "C") + toRomans(i%10, "I", "V", "X");
	}

	private static String toRomans(int i, String symbolI, String symbolV, String symbolX) {
		int moduloRest10 = i%10;
		if ( moduloRest10 == 0) {
			return "";
		}
		if ( moduloRest10 == 1) {
			return symbolI;
		}
		if ( moduloRest10 == 4) {
			return symbolI + symbolV;
		}
		if ( moduloRest10 == 5) {
			return symbolV;
		}
		if ( moduloRest10 == 9) {
			return symbolI + symbolX;
		}
			return  toRomans( moduloRest10 - 1, symbolI, symbolV, symbolX) + symbolI;
	}
	private static String getMultipleM(int i) {
		if (i == 0) {
			return "";
		}
		return "M" + getMultipleM(i-1);
	}

}

ConverterTest.java

import static org.junit.Assert.*;

import org.junit.Test;


public class ConverterTest {

	@Test
	public void acceptance_test() {
		assertEquals("MMCMXXXI", Converter.toRomans(2931));
	}
	@Test
	public void roman_for_1_should_be_I() {
		assertEquals("I", Converter.toRomans(1));
	}
	@Test
	public void roman_for_2_should_be_II() {
		assertEquals("II", Converter.toRomans(2));
	}
	@Test
	public void roman_for_4_should_be_IV() {
		assertEquals("IV", Converter.toRomans(4));
	}
	@Test
	public void roman_for_5_should_be_V() {
		assertEquals("V", Converter.toRomans(5));
	}
	@Test
	public void roman_for_7_should_be_VII() {
		assertEquals("VII", Converter.toRomans(7));
	}
	@Test
	public void roman_for_10_should_be_X() {
		assertEquals("X", Converter.toRomans(10));
	}
	@Test
	public void roman_for_9_should_be_IX() {
		assertEquals("IX", Converter.toRomans(9));
	}
	@Test
	public void roman_for_20_should_be_XX() {
		assertEquals("XX", Converter.toRomans(20));
	}
	@Test
	public void roman_for_21_should_be_XXI() {
		assertEquals("XXI", Converter.toRomans(21));
	}
	@Test
	public void roman_for_32_should_be_XXXII() {
		assertEquals("XXXII", Converter.toRomans(32));
	}
	@Test
	public void roman_for_29_should_be_XXIX() {
		assertEquals("XXIX", Converter.toRomans(29));
	}
	@Test
	public void roman_for_50_should_be_L() {
		assertEquals("L", Converter.toRomans(50));
	}
	@Test
	public void roman_for_74_should_be_LXXIV() {
		assertEquals("LXXIV", Converter.toRomans(74));
	}
	@Test
	public void roman_for_90_should_be_XC() {
		assertEquals("XC", Converter.toRomans(90));
	}
	@Test
	public void roman_for_100_should_be_C() {
		assertEquals("C", Converter.toRomans(100));
	}

}

retrospective

* on pensait plus tot à la structure de la solution
* on y est allé petit à petit, en se disant "voyons où ça nous mène"
* on est parti du bon côté dès le début
* + adapté que le Kata Bowling : réflection préliminaire moins indispensable
* le fait de tourner : c'est comme dans un vrai projet
* + on a réussi !