Add fuzzing (Go 1.18+) for Comma

Usage: go test -fuzz FuzzComma -v

comma_fuzz_test.go

@@ -0,0 +1,58 @@
+//go:build go1.18
+// +build go1.18
+
+package humanize_test
+
+import (
+ "math"
+ "strconv"
+ "strings"
+ "testing"
+
+ "github.com/dustin/go-humanize"
+)
+
+func FuzzComma(f *testing.F) {
+ f.Add(int64(0))
+ f.Add(int64(-1))
+ f.Add(int64(10))
+ f.Add(int64(100))
+ f.Add(int64(1000))
+ f.Add(int64(-1000))
+ f.Add(int64(math.MaxInt64))
+ f.Add(int64(math.MaxInt64) - 1)
+ f.Add(int64(math.MinInt64))
+ f.Add(int64(math.MinInt64) + 1)
+
+ f.Fuzz(func(t *testing.T, v int64) {
+ got := humanize.Comma(v)
+ gotNoCommas := strings.ReplaceAll(got, ",", "")
+ expected := strconv.FormatInt(v, 10)
+ if gotNoCommas != expected {
+ t.Fatalf("%d: got %q, expected %q", v, got, expected)
+ }
+
+ if v < 0 {
+ if got[0] != '-' {
+ t.Fatalf("%d: got: %q", v, got)
+ }
+ // Remove sign
+ got = got[1:]
+ }
+ // Check that commas are located every 3 digits
+ l := len(got)
+ for i := l - 1; i >= 0; i-- {
+ var ok bool
+ if (l-1-i)%4 == 3 {
+ ok = got[i] == ','
+ } else {
+ ok = got[i] >= '0' && got[i] <= '9'
+ }
+ if !ok {
+ t.Log(l - 1 - i)
+ t.Log((l - 1 - i) % 4)
+ t.Fatalf("%d: got: %q", v, got)
+ }
+ }
+ })
+}