[test] test whether the RCP supports the Link Metrics

This commit adds a test case to `cp-tests` to test whether the RCP
supports the Link Metrics.

tools/cp-caps/README.md

@@ -41,7 +41,7 @@ $ git clone [email protected]:openthread/ot-nrf528xx.git
 $ cd ot-nrf528xx/
 $ git submodule update --init
 $ ./script/bootstrap
-$ ./script/build nrf52840 UART_trans -DOT_DIAGNOSTIC=ON -DOT_CSL_RECEIVER=ON
+$ ./script/build nrf52840 UART_trans -DOT_DIAGNOSTIC=ON -DOT_CSL_RECEIVER=ON -DOT_LINK_METRICS_INITIATOR=ON -DOT_LINK_METRICS_SUBJECT=ON
 $ arm-none-eabi-objcopy -O ihex build/bin/ot-cli-ftd ot-cli-ftd.hex
 $ nrfjprog -f nrf52 --chiperase --program ot-cli-ftd.hex --reset
 ```
@@ -62,6 +62,7 @@ options:
   -h, --help           show this help message and exit
   -c, --csl            test whether the RCP supports CSL transmitter
   -d, --diag-commands  test whether the RCP supports all diag commands
+  -l, --link-metrics   test whether the RCP supports link metrics
   -p, --data-poll      test whether the RCP supports data poll
   -t, --throughput     test the Thread network 1-hop throughput
   -v, --verbose        output verbose information
@@ -146,6 +147,16 @@ Data Poll Parent ----------------------------------------- OK
 Data Poll Child ------------------------------------------ OK
 ```
 
+### Test Link Metrics
+
+The parameter `-l` or `--link-metrics` starts to test whether the RCP supports link metrics.
+
+```bash
+$ DUT_ADB_USB=1269UCKFZTAM95OR REF_CLI_SERIAL=/dev/ttyACM0 python3 ./tools/cp-caps/rcp_caps_test.py -l
+Link Metrics Initiator ----------------------------------- OK
+Link Metrics Subject ------------------------------------- OK
+```
+
 ### Test Throughput
 
 The parameter `-t` or `--throughput` starts to test the Thread network 1-hop throughput of the DUT.

tools/cp-caps/rcp_caps_test.py

@@ -38,6 +38,7 @@
 
 import otci
 from otci import OTCI
+from otci.types import Ip6Addr
 
 logging.basicConfig(level=logging.WARNING)
 
@@ -136,9 +137,62 @@ def test_throughput(self):
 
         self.__output_format_string('Throughput', self.__bitrate_to_string(results['receiver']['bitrate']))
 
+    def test_link_metrics(self):
+        """Test whether the DUT supports Link Metrics Initiator and Subject."""
+        self.__dataset = self.__get_default_dataset()
+
+        self.__dut.factory_reset()
+        self.__ref.factory_reset()
+
+        self.__dut.join(self.__dataset)
+        self.__dut.wait_for('state', 'leader')
+
+        self.__ref.join(self.__dataset)
+        self.__ref.wait_for('state', ['child', 'router'])
+
+        test_case = 'Link Metrics Initiator'
+        ref_linklocal_address = self.__ref.get_ipaddr_linklocal()
+        ret = self.__run_link_metrics_test_commands(initiator=self.__dut, subject_address=ref_linklocal_address)
+        self.__output_format_bool(test_case, ret)
+
+        test_case = 'Link Metrics Subject'
+        dut_linklocal_address = self.__dut.get_ipaddr_linklocal()
+        ret = self.__run_link_metrics_test_commands(initiator=self.__ref, subject_address=dut_linklocal_address)
+        self.__output_format_bool(test_case, ret)
+
+        self.__ref.leave()
+        self.__dut.leave()
+
     #
     # Private methods
     #
+    def __run_link_metrics_test_commands(self, initiator: OTCI, subject_address: Ip6Addr) -> bool:
+        seriesid = 1
+        series_flags = 'ldra'
+        link_metrics_flags = 'qr'
+        probe_length = 10
+
+        if not initiator.linkmetrics_config_enhanced_ack_register(subject_address, link_metrics_flags)
+            return False
+
+        if not initiator.linkmetrics_config_forward(subject_address, seriesid, series_flags, link_metrics_flags)
+            return False
+
+        initiator.linkmetrics_probe(subject_address, seriesid, probe_length)
+
+        results = initiator.linkmetrics_request_single(subject_address, link_metrics_flags)
+        if not 'lqi' in results.keys() and 'rssi' in results.keys()
+            return False
+
+        results = initiator.linkmetrics_request_forward(subject_address, seriesid)
+        if not 'lqi' in results.keys() and 'rssi' in results.keys()
+            return False
+
+        if not initiator.linkmetrics_config_enhanced_ack_clear(subject_address)
+            return False
+
+        return True
+
     def __ref_iperf3_server_task(self, bind_address: str, timeout: int):
         self.__ref.iperf3_server(bind_address, timeout=timeout)
 
@@ -535,6 +589,14 @@ def parse_arguments():
         help='test whether the RCP supports CSL transmitter',
     )
 
+    parser.add_argument(
+        '-l',
+        '--link-metrics',
+        action='store_true',
+        default=False,
+        help='test whether the RCP supports link metrics',
+    )
+
     parser.add_argument(
         '-d',
         '--diag-commands',
@@ -588,6 +650,9 @@ def main():
     if arguments.data_poll is True:
         rcp_caps.test_data_poll()
 
+    if arguments.link_metrics is True:
+        rcp_caps.test_link_metrics()
+
     if arguments.throughput:
         rcp_caps.test_throughput()