add key derivation test

crypto/key_derivation_test.go

@@ -0,0 +1,26 @@
+package crypto
+
+import (
+	"github.com/lucas-clemente/quic-go/protocol"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("KeyDerivation", func() {
+	It("derives proper keys", func() {
+		aead, err := DeriveKeysChacha20(
+			[]byte("0123456789012345678901"),
+			[]byte("nonce"),
+			protocol.ConnectionID(42),
+			[]byte("chlo"),
+			[]byte("scfg"),
+			[]byte("cert"),
+		)
+		Expect(err).ToNot(HaveOccurred())
+		chacha := aead.(*aeadChacha20Poly1305)
+		// If the IVs match, the keys will match too, since the keys are read earlier
+		Expect(chacha.myIV).To(Equal([]byte{0xf0, 0xf5, 0x4c, 0xa8}))
+		Expect(chacha.otherIV).To(Equal([]byte{0x75, 0xd8, 0xa2, 0x8d}))
+	})
+})