test_connection: add regression test for 1-byte packet handling

impl/test/unittest/test_connection.c

@@ -388,6 +388,8 @@ int main(void)
 	ASSERT_STATE(expected_state, conn);
 
 	// reset the transmitter
+	LOG(LVL_INFO, ">>> Transmitter restart test");
+
 	connection_restart_tx(&conn);
 	expected_state.next_packet_index = 0;
 
@@ -421,6 +423,8 @@ int main(void)
 	ASSERT_EQUAL_UINT(7, payload[1]);
 
 	// enqueue 10 more packets to test the sequence number overflow.
+	LOG(LVL_INFO, ">>> Testing sequence number overflow");
+
 	for(size_t i = 0; i < 10; i++) {
 		payload_len = 201;
 		static_payload[0] = i;
@@ -463,7 +467,7 @@ int main(void)
 
 	ASSERT_STATE(expected_state, conn);
 
-	LOG(LVL_INFO, "Queue overflow test:");
+	LOG(LVL_INFO, ">>> Queue overflow test:");
 
 	// nothing has been acknowledged so far, so we have 11 packets in the queue.
 	// It must be possible to add 4 more packets, but the 5th must fail.
@@ -506,6 +510,20 @@ int main(void)
 
 	ASSERT_STATE(expected_state, conn);
 
+	// Regression test: in the past, the program crashed if a packet with 1
+	// byte was decoded and passed to the connection instance. This can only
+	// happen due to decoder errors, because valid packets must contain at
+	// least the CRC which is 2 bytes large already.
+	LOG(LVL_INFO, ">>> Regression test: 1-byte packets must be handled correctly.");
+
+	// build corrupted packet
+	packet_buf[0] = 0x23;
+	packet_len = 1;
+
+	result_t result = connection_handle_packet(&conn, packet_buf, packet_len, &data_packet, &tx_req_rcvd);
+
+	ASSERT_RESULT(ERR_INTEGRITY, result);
+
 	// TODO: test connection close sequence
 
 	LOG(LVL_INFO, ">>> All assertions successful.");