Merge pull request #10 from donny-dont/negative-trunkate

Added negative truncation to helper function

template/helpers.go

@@ -17,6 +17,7 @@ package template
 import (
 	"fmt"
 	"net/url"
+	"math"
 	"regexp"
 	"strings"
 	"time"
@@ -100,12 +101,17 @@ func isFailure(conditional bool, options *raymond.Options) string {
 }
 
 func truncate(s string, len int) string {
-	if utf8.RuneCountInString(s) <= len {
+	if utf8.RuneCountInString(s) <= int(math.Abs(float64(len))) {
 		return s
 	}
 
 	runes := []rune(s)
 
+	if len < 0 {
+ 		len = -len
+		return string(runes[len:])
+	}
+
 	return string(runes[:len])
 }
 

template/helpers_test.go

@@ -53,6 +53,22 @@ func TestTruncate(t *testing.T) {
 	}
 }
 
+func TestNegativeTruncate(t *testing.T) {
+	vals := map[string]string{
+		"foobarz": "rz",
+		"foöäüüu": "üu",
+		"üpsßßßk": "ßk",
+		"1234567": "67",
+		"!'§$%&/": "&/",
+	}
+
+	for input, want := range vals {
+		if got := truncate(input, -5); got != want {
+			t.Errorf("Want transform %s to %s, got %s", input, want, got)
+		}
+	}
+}
+
 func TestSince(t *testing.T) {
 	t.Skip()
 }