fix(testutil): ensure GetRandomName never returns strings greater tha… (#14153)

testutil/names.go

@@ -10,6 +10,8 @@ import (
 
 var n atomic.Int64
 
+const maxNameLen = 32
+
 // GetRandomName returns a random name using moby/pkg/namesgenerator.
 // namesgenerator.GetRandomName exposes a retry parameter that appends
 // a pseudo-random number between 1 and 10 to its return value.
@@ -19,5 +21,20 @@ var n atomic.Int64
 // to the return value.
 func GetRandomName(t testing.TB) string {
 	t.Helper()
-	return namesgenerator.GetRandomName(0) + strconv.FormatInt(n.Add(1), 10)
+	name := namesgenerator.GetRandomName(0)
+	return incSuffix(name, n.Add(1), maxNameLen)
+}
+
+func incSuffix(s string, num int64, maxLen int) string {
+	suffix := strconv.FormatInt(num, 10)
+	if len(s)+len(suffix) <= maxLen {
+		return s + suffix
+	}
+	stripLen := (len(s) + len(suffix)) - maxLen
+	stripIdx := len(s) - stripLen
+	if stripIdx < 0 {
+		return ""
+	}
+	s = s[:stripIdx]
+	return s + suffix
 }