package pn;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import org.junit.Before;
import org.junit.Test;


public class AppTest {

    private RomanToNumbersConverter romanToNumbersConverter;

    @Before
    public void setUp() throws Exception {
        romanToNumbersConverter = new RomanToNumbersConverter();
    }

    @Test
    public void convertOne() {
        int result = romanToNumbersConverter.convert("I");
        assertEquals(1, result);
    }

    @Test
    public void testFive() {
        int result = romanToNumbersConverter.convert("V");
        assertEquals(5, result);
    }

    @Test
    public void testFour() {
        int result = romanToNumbersConverter.convert("IV");
        assertEquals(4, result);
    }

    @Test
    public void testSix() {
        int result = romanToNumbersConverter.convert("VI");
        assertEquals(6, result);
    }

    @Test
    public void testEight() {
        int result = romanToNumbersConverter.convert("VIII");
        assertEquals(8, result);
    }

    @Test
    public void testEleven() {
        int result = romanToNumbersConverter.convert("XI");
        assertEquals(11, result);
    }

    @Test
    public void testSixtyEight() {
        int result = romanToNumbersConverter.convert("LXVIII");
        assertEquals(68, result);
    }

    @Test
    public void testOneHundreadAndEleven() {
        int result = romanToNumbersConverter.convert("XI");
        assertEquals(11, result);

    }
}


package pn;

import java.util.HashMap;

public class RomanToNumbersConverter {

    private HashMap<String, Integer> romanNumbers;

    public RomanToNumbersConverter() {
        this.romanNumbers = new HashMap<>();
        romanNumbers.put("I", 1);
        romanNumbers.put("V", 5);
        romanNumbers.put("X", 10);
        romanNumbers.put("L", 50);
        romanNumbers.put("C", 100);
    }

    public int convert(String romanNumber) {
        if (romanNumber.length() == 1) {
            return romanNumbers.get(romanNumber);
        }
        int result = 0;
        char[] romanNumberArray = romanNumber.toCharArray();

        for (int character = romanNumber.length() - 1; character > 0; character--) {
            String characterAsString = Character.toString(romanNumberArray[character]);
            String previousCharacterAsString = Character.toString(romanNumberArray[character-1]);
            int currentNumber = romanNumbers.get(characterAsString);

            if (romanNumbers.get(previousCharacterAsString) < currentNumber) {
                currentNumber = currentNumber - romanNumbers.get(previousCharacterAsString);
            } else if (romanNumbers.get(previousCharacterAsString) > currentNumber) {

                currentNumber = currentNumber + romanNumbers.get(previousCharacterAsString);

            }
            result += currentNumber;
        }
        return result;
    }
}