select the right null AEAD algorithm depending on the version

crypto/null_aead_test.go

@@ -0,0 +1,17 @@
+package crypto
+
+import (
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("NullAEAD", func() {
+	It("selects the right FVN variant", func() {
+		Expect(NewNullAEAD(protocol.PerspectiveClient, protocol.Version39)).To(Equal(&nullAEADFNV128a{
+			perspective: protocol.PerspectiveClient,
+			version:     protocol.Version39,
+		}))
+		Expect(NewNullAEAD(protocol.PerspectiveClient, protocol.VersionTLS)).To(Equal(&nullAEADFNV64a{}))
+	})
+})