tests/net: add stub test for gcoap_forward_proxy

This adds enough to do compile testing for gcoap_forward_proxy.
A proper test would still be needed, though.

This still already exposed compilation issues.

tests/net/gcoap_forward_proxy/Makefile

@@ -0,0 +1,33 @@
+include ../Makefile.net_common
+
+USEMODULE += embunit
+
+USEMODULE += auto_init_gnrc_netif
+USEMODULE += fmt
+USEMODULE += ipv4_addr
+USEMODULE += ipv6_addr
+USEMODULE += gcoap_forward_proxy
+USEMODULE += gnrc_ipv6_default
+USEMODULE += netdev_default
+USEMODULE += od
+USEMODULE += shell
+USEMODULE += shell_cmds_default
+
+COAPS ?= 1
+
+ifeq (1,$(COAPS))
+  USEMODULE += gcoap_dtls
+  USEMODULE += prng_sha256prng
+  USEPKG += tinydtls
+  KCONFIG_ADD_CONFIG += $(CURDIR)/coaps.config
+endif
+
+CFLAGS += -DTEST_SUITES
+CFLAGS += -DHAS_SOCK_DNS_MOCK=1
+
+include $(RIOTBASE)/Makefile.include
+
+ifneq (,$(filter native native64,$(BOARD)))
+test: PORT=
+$(call target-export-variables,test,PORT)
+endif

tests/net/gcoap_forward_proxy/Makefile.ci

@@ -0,0 +1,60 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    airfy-beacon \
+    arduino-duemilanove \
+    arduino-leonardo \
+    arduino-mega2560 \
+    arduino-nano \
+    arduino-uno \
+    atmega1284p \
+    atmega328p \
+    atmega328p-xplained-mini \
+    atmega8 \
+    atxmega-a3bu-xplained \
+    blackpill-stm32f103c8 \
+    bluepill-stm32f030c8 \
+    bluepill-stm32f103c8 \
+    calliope-mini \
+    derfmega128 \
+    hifive1 \
+    hifive1b \
+    i-nucleo-lrwan1 \
+    im880b \
+    mega-xplained \
+    microbit \
+    microduino-corerf \
+    msb-430 \
+    msb-430h \
+    nrf51dongle \
+    nrf6310 \
+    nucleo-c031c6 \
+    nucleo-f030r8 \
+    nucleo-f031k6 \
+    nucleo-f042k6 \
+    nucleo-f070rb \
+    nucleo-f072rb \
+    nucleo-f302r8 \
+    nucleo-f303k8 \
+    nucleo-f334r8 \
+    nucleo-l011k4 \
+    nucleo-l031k6 \
+    nucleo-l053r8 \
+    olimex-msp430-h1611 \
+    olimex-msp430-h2618 \
+    samd10-xmini \
+    saml10-xpro \
+    saml11-xpro \
+    slstk3400a \
+    stk3200 \
+    stm32f030f4-demo \
+    stm32f0discovery \
+    stm32f7508-dk \
+    stm32g0316-disco \
+    stm32l0538-disco \
+    stm32mp157c-dk2 \
+    telosb \
+    waspmote-pro \
+    weact-g030f6 \
+    yunjia-nrf51822 \
+    z1 \
+    zigduino \
+    #

tests/net/gcoap_forward_proxy/README.md

@@ -0,0 +1,5 @@
+TODO
+====
+
+This application is here to ensure that the `gcoap_forward_proxy` is at least compile tested.
+A proper test will hopefully be implemented some day that replaces this stub.

tests/net/gcoap_forward_proxy/main.c

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2024 ML!PA Consulting GmbH
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       test application for the GCoAP forward proxy
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@posteo.net>
+ * @}
+ */
+
+#include "msg.h"
+#include "shell.h"
+
+#define MAIN_QUEUE_SIZE (4)
+static msg_t _main_msg_queue[MAIN_QUEUE_SIZE];
+
+int main(void)
+{
+    msg_init_queue(_main_msg_queue, MAIN_QUEUE_SIZE);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}