diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index 6c10992..f841293 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -639,7 +639,11 @@
 	// the server believes it has actually negotiated.
 	SendCipherSuite uint16
 
-	// AppDataAfterChangeCipherSpec, if not null, causes application data to
+	// AppDataBeforeHandshake, if not nil, causes application data to be
+	// sent immediately before the first handshake message.
+	AppDataBeforeHandshake []byte
+
+	// AppDataAfterChangeCipherSpec, if not nil, causes application data to
 	// be sent immediately after ChangeCipherSpec.
 	AppDataAfterChangeCipherSpec []byte
 
diff --git a/ssl/test/runner/conn.go b/ssl/test/runner/conn.go
index b755c46..cf6700d 100644
--- a/ssl/test/runner/conn.go
+++ b/ssl/test/runner/conn.go
@@ -1287,6 +1287,9 @@
 		})
 		c.conn.Write([]byte{alertLevelError, byte(alertInternalError)})
 	}
+	if data := c.config.Bugs.AppDataBeforeHandshake; data != nil {
+		c.writeRecord(recordTypeApplicationData, data)
+	}
 	if c.isClient {
 		c.handshakeErr = c.clientHandshake()
 	} else {
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 6c774eb..950c02a 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -1308,6 +1308,48 @@
 			flags:            []string{"-async"},
 		},
 		{
+			name: "AppDataBeforeHandshake",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataBeforeHandshake: []byte("TEST MESSAGE"),
+				},
+			},
+			shouldFail:    true,
+			expectedError: ":UNEXPECTED_RECORD:",
+		},
+		{
+			name: "AppDataBeforeHandshake-Empty",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataBeforeHandshake: []byte{},
+				},
+			},
+			shouldFail:    true,
+			expectedError: ":UNEXPECTED_RECORD:",
+		},
+		{
+			protocol: dtls,
+			name:     "AppDataBeforeHandshake-DTLS",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataBeforeHandshake: []byte("TEST MESSAGE"),
+				},
+			},
+			shouldFail:    true,
+			expectedError: ":UNEXPECTED_RECORD:",
+		},
+		{
+			protocol: dtls,
+			name:     "AppDataBeforeHandshake-DTLS-Empty",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataBeforeHandshake: []byte{},
+				},
+			},
+			shouldFail:    true,
+			expectedError: ":UNEXPECTED_RECORD:",
+		},
+		{
 			name: "AppDataAfterChangeCipherSpec",
 			config: Config{
 				Bugs: ProtocolBugs{
@@ -1318,6 +1360,16 @@
 			expectedError: ":DATA_BETWEEN_CCS_AND_FINISHED:",
 		},
 		{
+			name: "AppDataAfterChangeCipherSpec-Empty",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataAfterChangeCipherSpec: []byte{},
+				},
+			},
+			shouldFail:    true,
+			expectedError: ":DATA_BETWEEN_CCS_AND_FINISHED:",
+		},
+		{
 			protocol: dtls,
 			name:     "AppDataAfterChangeCipherSpec-DTLS",
 			config: Config{
@@ -1329,6 +1381,17 @@
 			// application data.
 		},
 		{
+			protocol: dtls,
+			name:     "AppDataAfterChangeCipherSpec-DTLS-Empty",
+			config: Config{
+				Bugs: ProtocolBugs{
+					AppDataAfterChangeCipherSpec: []byte{},
+				},
+			},
+			// BoringSSL's DTLS implementation will drop the out-of-order
+			// application data.
+		},
+		{
 			name: "AlertAfterChangeCipherSpec",
 			config: Config{
 				Bugs: ProtocolBugs{