diff --git a/internal/testkit/testkit.go b/internal/testkit/testkit.go
index 8705162..e459095 100644
--- a/internal/testkit/testkit.go
+++ b/internal/testkit/testkit.go
@@ -130,8 +130,7 @@ func (f *TestFile) HMAC() {
 	f.HMACLine(h.Sum(nil))
 }
 
-func (f *TestFile) Nonce() {
-	nonce := f.Rand(16)
+func (f *TestFile) Nonce(nonce []byte) {
 	f.streamKey = make([]byte, 32)
 	hkdf.New(sha256.New, f.fileKey, nonce, []byte("payload")).Read(f.streamKey)
 	f.Buf.Write(nonce)
@@ -152,7 +151,7 @@ func (f *TestFile) PayloadChunkFinal(plaintext []byte) {
 }
 
 func (f *TestFile) Payload(plaintext string) {
-	f.Nonce()
+	f.Nonce(f.Rand(16))
 	f.PayloadChunkFinal([]byte(plaintext))
 }
 
diff --git a/testdata/empty_payload.go b/testdata/stream_empty_payload.go
similarity index 100%
rename from testdata/empty_payload.go
rename to testdata/stream_empty_payload.go
diff --git a/testdata/empty_payload.test b/testdata/stream_empty_payload.test
similarity index 100%
rename from testdata/empty_payload.test
rename to testdata/stream_empty_payload.test
diff --git a/testdata/stream_last_chunk_empty.go b/testdata/stream_last_chunk_empty.go
new file mode 100644
index 0000000..8cebe0e
--- /dev/null
+++ b/testdata/stream_last_chunk_empty.go
@@ -0,0 +1,32 @@
+// Copyright 2022 The age Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+
+package main
+
+import (
+	"bytes"
+	"encoding/hex"
+
+	"filippo.io/age/internal/testkit"
+)
+
+func main() {
+	f := testkit.NewTestFile()
+	// Reuse the file key and nonce from a previous test vector to avoid
+	// bloating the git history with two versions that can't be compressed.
+	fileKey, _ := hex.DecodeString("7aa5bdac0e6afeed3dd0a7eccb42af44")
+	f.FileKey(fileKey)
+	f.VersionLine("v1")
+	f.X25519(testkit.TestX25519Identity)
+	f.HMAC()
+	nonce, _ := hex.DecodeString("c82f71eb82029b77136399e485e879f4")
+	f.Nonce(nonce)
+	f.PayloadChunk(bytes.Repeat([]byte{0}, 64*1024))
+	f.PayloadChunkFinal([]byte{})
+	f.Comment("final STREAM chunk can't be empty unless whole payload is empty")
+	f.ExpectPayloadFailure()
+	f.Generate()
+}
diff --git a/cmd/age/testdata/fail_last_empty.age b/testdata/stream_last_chunk_empty.test
similarity index 99%
rename from cmd/age/testdata/fail_last_empty.age
rename to testdata/stream_last_chunk_empty.test
index 3f67f5b..8e03661 100644
Binary files a/cmd/age/testdata/fail_last_empty.age and b/testdata/stream_last_chunk_empty.test differ
diff --git a/testdata/stream_last_chunk_full.go b/testdata/stream_last_chunk_full.go
new file mode 100644
index 0000000..a86efe7
--- /dev/null
+++ b/testdata/stream_last_chunk_full.go
@@ -0,0 +1,29 @@
+// Copyright 2022 The age Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+
+package main
+
+import (
+	"bytes"
+	"encoding/hex"
+
+	"filippo.io/age/internal/testkit"
+)
+
+func main() {
+	f := testkit.NewTestFile()
+	// Reuse the file key and nonce from a previous test vector to avoid
+	// bloating the git history with two versions that can't be compressed.
+	fileKey, _ := hex.DecodeString("5085919e0d59b19d6cbd00330f03861c")
+	f.FileKey(fileKey)
+	f.VersionLine("v1")
+	f.X25519(testkit.TestX25519Identity)
+	f.HMAC()
+	nonce, _ := hex.DecodeString("32521791a6f22e11637fb69ead3f2d5f")
+	f.Nonce(nonce)
+	f.PayloadChunkFinal(bytes.Repeat([]byte{0}, 64*1024))
+	f.Generate()
+}
diff --git a/cmd/age/testdata/good_last_full.age b/testdata/stream_last_chunk_full.test
similarity index 99%
rename from cmd/age/testdata/good_last_full.age
rename to testdata/stream_last_chunk_full.test
index 78d62d8..bc4baae 100644
Binary files a/cmd/age/testdata/good_last_full.age and b/testdata/stream_last_chunk_full.test differ