Do not return an error on out of bounds (return "OOB" string instead)

convertroman.go

@@ -1,17 +1,10 @@
 package convertroman
 
-// Currently only supports Roman Numerals without viniculum (1-3999) and will throw an error for
-// numbers outside of that range. See here for details on viniculum:
+// Currently only supports Roman Numerals without viniculum (1-3999; "OOB" is returned for values outside this range)
+// See here for details on viniculum:
 // https://en.wikipedia.org/wiki/Roman_numerals#Large_numbers
 
-import (
-	"errors"
-)
-
 var (
-	// IntegerOutOfBounds - error for when the integer provided is invalid and unable to be converted to a roman numeral
-	IntegerOutOfBounds = errors.New("integer must be between 1 and 3999")
-
 	// lookup arrays used for converting from an int to a roman numeral extremely quickly.
 	// method from here: https://rosettacode.org/wiki/Roman_numerals/Encode#Go
 	r0 = [10]string{"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}
@@ -21,13 +14,13 @@ var (
 )
 
 // FromInt converts an integer value to a roman numeral string.
-// An error is returned if the integer is not between 1 and 3999.
-func FromInt(input int) (string, error) {
+// "OOB" is returned if the integer is not between 1 and 3999.
+func FromInt(input int) string {
 	// ensure provided integer is within the valid range
 	if input < 1 || input > 3999 {
-		return "OOB", IntegerOutOfBounds
+		return "OOB"
 	}
 
 	// convert the integer to a roman numeral string and return it
-	return r3[input%1e4/1e3] + r2[input%1e3/1e2] + r1[input%100/10] + r0[input%10], nil
+	return r3[input%1e4/1e3] + r2[input%1e3/1e2] + r1[input%100/10] + r0[input%10]
 }

convertroman_test.go

@@ -26,35 +26,34 @@ var testCases = map[string]int{
 
 func TestFromInt(t *testing.T) {
 	for expected, input := range testCases {
-		out, err := FromInt(input)
-		if err != nil {
-			t.Errorf("IntToString(%d) returned an error %s", input, err.Error())
-		}
-		if out != expected {
-			t.Errorf("IntToString(%d) = %s; want %s", input, out, expected)
+		out := FromInt(input)
+		if out == "OOB" {
+			t.Errorf("FromInt(%d) returned an OOB (out of bounds) error", input)
+		} else if out != expected {
+			t.Errorf("FromInt(%d) = %s; want %s", input, out, expected)
 		}
 	}
-	_, err := FromInt(100000)
-	if err == nil {
-		t.Errorf("IntToString(%d) expected an error", 100000)
+	out := FromInt(100000)
+	if out != "OOB" {
+		t.Errorf("FromInt(%d) expected an error", 100000)
 	}
-	_, err = FromInt(0)
-	if err == nil {
-		t.Errorf("IntToString(%d) expected an error", 0)
+	out = FromInt(0)
+	if out != "OOB" {
+		t.Errorf("FromInt(%d) expected an error", 0)
 	}
 }
 
 func BenchmarkFromInt(b *testing.B) {
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
-		_, _ = FromInt(3999)
+		_ = FromInt(3999)
 	}
 }
 
 func ExampleFromInt() {
-	roman, err := FromInt(4)
-	if err != nil {
-		panic(err)
+	roman := FromInt(4)
+	if roman == "OOB" {
+		panic("Input integer is out of bounds")
 	}
 	fmt.Println(roman == "IV") // True
 }