diff --git a/integrationtests/self/mitm_test.go b/integrationtests/self/mitm_test.go
index 860da5af..46031edc 100644
--- a/integrationtests/self/mitm_test.go
+++ b/integrationtests/self/mitm_test.go
@@ -328,8 +328,8 @@ var _ = Describe("MITM test", func() {
 				// expects hdr from an Initial packet intercepted from client
 				sendForgedInitialPacketWithAck := func(conn net.PacketConn, remoteAddr net.Addr, hdr *wire.Header) {
 					// Fake Initial with ACK for packet 2 (unsent)
-					ackFrame := testutils.ComposeAckFrame(2, 2)
-					initialPacket := testutils.ComposeInitialPacket(hdr.DestConnectionID, hdr.SrcConnectionID, hdr.Version, hdr.DestConnectionID, []wire.Frame{ackFrame})
+					ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 2, Largest: 2}}}
+					initialPacket := testutils.ComposeInitialPacket(hdr.DestConnectionID, hdr.SrcConnectionID, hdr.Version, hdr.DestConnectionID, []wire.Frame{ack})
 					_, err := conn.WriteTo(initialPacket, remoteAddr)
 					Expect(err).ToNot(HaveOccurred())
 				}
diff --git a/internal/testutils/testutils.go b/internal/testutils/testutils.go
index 51851ad9..b4ed9147 100644
--- a/internal/testutils/testutils.go
+++ b/internal/testutils/testutils.go
@@ -11,9 +11,6 @@ import (
 // Utilities for simulating packet injection and man-in-the-middle (MITM) attacker tests.
 // Do not use for non-testing purposes.
 
-// CryptoFrameType uses same types as messageType in crypto_setup.go
-type CryptoFrameType uint8
-
 // writePacket returns a new raw packet with the specified header and payload
 func writePacket(hdr *wire.ExtendedHeader, data []byte) []byte {
 	buf := &bytes.Buffer{}
@@ -30,38 +27,6 @@ func packRawPayload(version protocol.VersionNumber, frames []wire.Frame) []byte
 	return buf.Bytes()
 }
 
-// ComposeCryptoFrame returns a new empty crypto frame of the specified
-// type padded to size bytes with zeroes
-func ComposeCryptoFrame(cft CryptoFrameType, size int) *wire.CryptoFrame {
-	data := make([]byte, size)
-	data[0] = byte(cft)
-	return &wire.CryptoFrame{
-		Offset: 0,
-		Data:   data,
-	}
-}
-
-// ComposeConnCloseFrame returns a new Connection Close frame with a generic error
-func ComposeConnCloseFrame() *wire.ConnectionCloseFrame {
-	return &wire.ConnectionCloseFrame{
-		IsApplicationError: true,
-		ErrorCode:          0,
-		ReasonPhrase:       "mitm attacker",
-	}
-}
-
-// ComposeAckFrame returns a new Ack Frame that acknowledges all packets between smallest and largest
-func ComposeAckFrame(smallest protocol.PacketNumber, largest protocol.PacketNumber) *wire.AckFrame {
-	ackRange := wire.AckRange{
-		Smallest: smallest,
-		Largest:  largest,
-	}
-	return &wire.AckFrame{
-		AckRanges: []wire.AckRange{ackRange},
-		DelayTime: 0,
-	}
-}
-
 // ComposeInitialPacket returns an Initial packet encrypted under key
 // (the original destination connection ID) containing specified frames
 func ComposeInitialPacket(srcConnID protocol.ConnectionID, destConnID protocol.ConnectionID, version protocol.VersionNumber, key protocol.ConnectionID, frames []wire.Frame) []byte {
diff --git a/session_test.go b/session_test.go
index 31681ca7..67fb5bf6 100644
--- a/session_test.go
+++ b/session_test.go
@@ -2956,8 +2956,8 @@ var _ = Describe("Client Session", func() {
 		// Illustrates that an injected Initial with an ACK frame for an unsent packet causes
 		// the connection to immediately break down
 		It("fails on Initial-level ACK for unsent packet", func() {
-			ackFrame := testutils.ComposeAckFrame(0, 0)
-			initialPacket := testutils.ComposeInitialPacket(destConnID, srcConnID, sess.version, destConnID, []wire.Frame{ackFrame})
+			ack := &wire.AckFrame{AckRanges: []wire.AckRange{{Smallest: 2, Largest: 2}}}
+			initialPacket := testutils.ComposeInitialPacket(destConnID, srcConnID, sess.version, destConnID, []wire.Frame{ack})
 			tracer.EXPECT().ReceivedPacket(gomock.Any(), gomock.Any(), gomock.Any())
 			Expect(sess.handlePacketImpl(wrapPacket(initialPacket))).To(BeFalse())
 		})
@@ -2965,7 +2965,10 @@ var _ = Describe("Client Session", func() {
 		// Illustrates that an injected Initial with a CONNECTION_CLOSE frame causes
 		// the connection to immediately break down
 		It("fails on Initial-level CONNECTION_CLOSE frame", func() {
-			connCloseFrame := testutils.ComposeConnCloseFrame()
+			connCloseFrame := &wire.ConnectionCloseFrame{
+				IsApplicationError: true,
+				ReasonPhrase:       "mitm attacker",
+			}
 			initialPacket := testutils.ComposeInitialPacket(destConnID, srcConnID, sess.version, destConnID, []wire.Frame{connCloseFrame})
 			tracer.EXPECT().ReceivedPacket(gomock.Any(), gomock.Any(), gomock.Any())
 			Expect(sess.handlePacketImpl(wrapPacket(initialPacket))).To(BeTrue())