***roman: add convert to arabic, the real one

roman/roman.go

@@ -37,5 +37,13 @@ func ConvertToRoman(arabic int) string {
 }
 
 func ConvertToArabic(roman string) int {
-	return 1
+	var converted int
+	for _, numeral := range allRomanNumerals {
+		for strings.HasPrefix(roman, numeral.Symbol) {
+			converted += numeral.Value
+			// roman = roman[len(numeral.Symbol):]
+			roman = strings.TrimPrefix(roman, numeral.Symbol)
+		}
+	}
+	return converted
 }

roman/roman_test.go

@@ -54,7 +54,7 @@ func TestRomanNemerals(t *testing.T) {
 }
 
 func TestConvertingToArabic(t *testing.T) {
-	for _, test := range cases[:1] {
+	for _, test := range cases {
 		t.Run(fmt.Sprintf("%q gets converted to %d", test.Roman, test.Arabic), func(t *testing.T) {
 			got := ConvertToArabic(test.Roman)
 			want := test.Arabic