samples/net/lwm2m_client: Move from native_posix to native_sim

* In the sample doc, replace native_posix references with native_sim
* Provide an overlay for native_sim
* Enable native_sim in the test yaml

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

samples/net/lwm2m_client/README.rst

@@ -68,7 +68,7 @@ Build the lwm2m-client sample application like this:
    :compact:
 
 The easiest way to setup this sample application is to build and run it
-as native POSIX application or as a QEMU target using the default configuration :file:`prj.conf`.
+as a native_sim application or as a QEMU target using the default configuration :file:`prj.conf`.
 This requires a small amount of setup described in :ref:`networking_with_eth_qemu`, :ref:`networking_with_qemu` and :ref:`networking_with_native_posix`.
 
 Download and run the latest build of the Leshan Demo Server:

samples/net/lwm2m_client/boards/native_sim.conf

@@ -0,0 +1,5 @@
+CONFIG_DNS_RESOLVER=y
+CONFIG_DNS_SERVER_IP_ADDRESSES=y
+CONFIG_DNS_SERVER1="192.0.2.2"
+CONFIG_LWM2M_DNS_SUPPORT=y
+CONFIG_NET_CONFIG_MY_IPV4_GW="192.0.2.2"

samples/net/lwm2m_client/sample.yaml

@@ -10,6 +10,7 @@ tests:
       - frdm_k64f
       - pinnacle_100_dvk
       - mg100
+      - native_sim
     integration_platforms:
       - qemu_x86
     tags:
@@ -18,7 +19,9 @@ tests:
   sample.net.lwm2m_client.all_objects:
     harness: net
     depends_on: netif
-    platform_allow: qemu_x86
+    platform_allow:
+      - qemu_x86
+      - native_sim
     integration_platforms:
       - qemu_x86
     tags:
@@ -43,6 +46,7 @@ tests:
       - frdm_k64f
       - pinnacle_100_dvk
       - mg100
+      - native_sim
     integration_platforms:
       - qemu_x86
     tags:
@@ -63,7 +67,9 @@ tests:
     harness: net
     depends_on: netif
     extra_args: OVERLAY_CONFIG=overlay-queue.conf
-    platform_allow: qemu_x86
+    platform_allow:
+      - qemu_x86
+      - native_sim
     integration_platforms:
       - qemu_x86
     tags: