fix: truncate utf8 strings correctly

Fixes: #1510

converters.go

@@ -33,8 +33,7 @@ func (c *converters) parseNumField(r string) (s int) {
 }
 
 func (c *converters) parseStringField(r string) (s string) {
-	s = strings.TrimSpace(r)
-	return s
+	return strings.TrimSpace(r)
 }
 
 func (c *converters) parseStringFieldWithOpts(r string, opts *ValidateOpts) string {
@@ -90,8 +89,9 @@ func (c *converters) alphaField(s string, max uint) string {
 	}
 
 	ln := uint(count)
-	if ln > max {
-		return s[:max]
+	if ln > max && len(s) >= count {
+		// Find which index corresponds to the max characters allowed
+		return string([]rune(s)[:max])
 	}
 
 	m := int(max) - int(ln) //nolint:gosec
@@ -150,8 +150,9 @@ func (c *converters) stringField(s string, max uint) string {
 	}
 
 	ln := uint(count)
-	if ln > max {
-		return s[:max]
+	if ln > max && len(s) >= count {
+		// Find which index corresponds to the max characters allowed
+		return string([]rune(s)[:max])
 	}
 
 	m := int(max) - int(ln) //nolint:gosec

converters_test.go

@@ -306,3 +306,16 @@ func TestLeastSignificantDigits(t *testing.T) {
 		}
 	}
 }
+
+func TestConvertors_UTF8Truncation(t *testing.T) {
+	c := converters{}
+
+	require.Equal(t, "John Doe       ", c.alphaField("John Doe", 15))
+	require.Equal(t, "0000000John Doe", c.stringField("John Doe", 15))
+
+	require.Equal(t, "Testée Samples ", c.alphaField("Testée Samples", 15))
+	require.Equal(t, "0Testée Samples", c.stringField("Testée Samples", 15))
+
+	require.Equal(t, "Testée Samples0", c.alphaField("Testée Samples01", 15))
+	require.Equal(t, "Testée Samples0", c.stringField("Testée Samples01", 15))
+}

entryDetail_test.go

@@ -28,6 +28,8 @@ import (
 	"testing"
 
 	"github.com/moov-io/base"
+
+	"github.com/stretchr/testify/require"
 )
 
 // mockEntryDetail creates an entry detail
@@ -766,3 +768,11 @@ func TestEntryDetail__InvalidCheckDigitNotAllowedWithNullValidateOpt(t *testing.
 	ed = nil
 	ed.SetValidation(&ValidateOpts{})
 }
+
+func TestEntryDetail_UTF8Truncation(t *testing.T) {
+	ed := mockEntryDetail()
+	ed.IdentificationNumber = "Testée Samples01"
+
+	require.Equal(t, "Testée Samples0", ed.IdentificationNumberField())
+	require.Equal(t, "Testée Samples01", ed.IdentificationNumber)
+}

reader_test.go

@@ -988,9 +988,12 @@ func testFileBatchControlValidate(t testing.TB) {
 	bh := mockBatchHeader()
 	ed := mockEntryDetail()
 	bc := mockBatchControl()
-	bc.CompanyIdentification = "B1G C0MP®NY"
+	bc.CompanyIdentification = "B1G C0MPANY"
+
 	line := bh.String() + "\n" + ed.String() + "\n" + bc.String()
+
 	r := NewReader(strings.NewReader(line))
+
 	_, err := r.Read()
 	if !base.Has(err, NewErrBatchHeaderControlEquality(220, 200)) {
 		t.Errorf("%T: %s", err, err)