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

testutil/names_internal_test.go

@@ -0,0 +1,52 @@
+package testutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIncSuffix(t *testing.T) {
+	t.Parallel()
+
+	for _, tt := range []struct {
+		s      string
+		num    int64
+		maxLen int
+		want   string
+	}{
+		{
+			s:      "foo",
+			num:    1,
+			maxLen: 4,
+			want:   "foo1",
+		},
+		{
+			s:      "foo",
+			num:    42,
+			maxLen: 3,
+			want:   "f42",
+		},
+		{
+			s:      "foo",
+			num:    3,
+			maxLen: 2,
+			want:   "f3",
+		},
+		{
+			s:      "foo",
+			num:    4,
+			maxLen: 1,
+			want:   "4",
+		},
+		{
+			s:      "foo",
+			num:    0,
+			maxLen: 0,
+			want:   "",
+		},
+	} {
+		actual := incSuffix(tt.s, tt.num, tt.maxLen)
+		assert.Equal(t, tt.want, actual)
+	}
+}