lib,rlc_am_nr: fix checking some statistics in unit test

lib/test/rlc/rlc_am_nr_test.cc

@@ -750,7 +750,7 @@ int retx_segment_test()
     }
     TESTASSERT(0 == rlc1.get_buffer_state());
   }
-  /*
+
   // Check statistics
   rlc_bearer_metrics_t metrics1 = rlc1.get_metrics();
   rlc_bearer_metrics_t metrics2 = rlc2.get_metrics();
@@ -761,17 +761,20 @@ int retx_segment_test()
   TESTASSERT_EQ(15, metrics1.num_tx_sdu_bytes);
   TESTASSERT_EQ(0, metrics1.num_rx_sdu_bytes);
   TESTASSERT_EQ(0, metrics1.num_lost_sdus);
+
   // PDU metrics
-    TESTASSERT_EQ(5 + 3, metrics1.num_tx_pdus);      // 3 re-transmissions
+  TESTASSERT_EQ(15 + 3, metrics1.num_tx_pdus);  // 15 PDUs + 3 re-transmissions
   TESTASSERT_EQ(2, metrics1.num_rx_pdus);       // Two status PDU
-    TESTASSERT_EQ(38, metrics1.num_tx_pdu_bytes);    // 2 Bytes * NBUFFS (header size) + NBUFFS * 3 (data) +
+  TESTASSERT_EQ(78, metrics1.num_tx_pdu_bytes); // 3 Bytes * 5 (5 PDUs without SO) + 10 * 5 (10 PDUs with SO)
-                                                     // 3 (1 retx no SO) + 2 * 5 (2 retx with SO) = 38
+                                                // 3 (1 retx no SO) + 2 * 5 (2 retx with SO) = 78
-    TESTASSERT_EQ(3 + 5, metrics1.num_rx_pdu_bytes); // Two status PDU (one with a NACK)
+  TESTASSERT_EQ(24, metrics1.num_rx_pdu_bytes); // Two status PDU. One with just an ack (3 bytes)
+                                                // Another with 3 NACKs all with SO. (3 + 3*6 bytes)
   TESTASSERT_EQ(0, metrics1.num_lost_sdus);     // No lost SDUs
 
   // PDU metrics
   TESTASSERT_EQ(0, metrics2.num_tx_sdus);
   TESTASSERT_EQ(5, metrics2.num_rx_sdus);
+  /*
   TESTASSERT_EQ(0, metrics2.num_tx_sdu_bytes);
   TESTASSERT_EQ(15, metrics2.num_rx_sdu_bytes); // 5 SDUs, 3 bytes each
   TESTASSERT_EQ(0, metrics2.num_lost_sdus);