tests/saul_drivers: add saul build test application

tests/saul_drivers/Makefile

@@ -0,0 +1,52 @@
+BOARD ?= stm32f4discovery
+include ../Makefile.tests_common
+
+# Only build on a subset of boards (one per arch supported and
+# with enough features provided)
+BOARD_WHITELIST ?= \
+    atmega256rfr2-xpro \
+    esp32-wroom-32 \
+    stm32f4discovery \
+    #
+
+# Get the list of drivers with a SAUL interface (without saul periph)
+DRIVERS_DIR = $(RIOTBASE)/drivers
+DRIVERS_WITH_SAUL_PATHS = $(filter-out $(wildcard $(DRIVERS_DIR)/saul/*_saul.c),$(wildcard $(DRIVERS_DIR)/*/*_saul.c))
+DRIVERS ?= $(subst _saul.c,,$(notdir $(DRIVERS_WITH_SAUL_PATHS)))
+USEMODULE += $(DRIVERS)
+
+# Somes drivers with submodules needs special care to select a precise driver variant
+ifneq (,$(filter adcxx1c,$(DRIVERS)))
+  USEMODULE += adc081c
+endif
+ifneq (,$(filter apds99xx,$(DRIVERS)))
+  USEMODULE += apds9960
+endif
+ifneq (,$(filter bme680,$(DRIVERS)))
+  USEMODULE += bme680_i2c
+endif
+ifneq (,$(filter lm75,$(DRIVERS)))
+  USEMODULE += tmp1075
+endif
+ifneq (,$(filter lpsxxx,$(DRIVERS)))
+  USEMODULE += lps22hh
+endif
+ifneq (,$(filter mhz19,$(DRIVERS)))
+  USEMODULE += mhz19_uart
+endif
+ifneq (,$(filter mpu9x50,$(DRIVERS)))
+  USEMODULE += mpu9150
+endif
+ifneq (,$(filter pcf857x,$(DRIVERS)))
+  USEMODULE += pcf8575
+endif
+ifneq (,$(filter si70xx,$(DRIVERS)))
+  USEMODULE += si7021
+endif
+ifneq (,$(filter tmp00x,$(DRIVERS)))
+  USEMODULE += tmp006
+endif
+
+USEMODULE += saul_default
+
+include $(RIOTBASE)/Makefile.include

tests/saul_drivers/README.md

@@ -0,0 +1,9 @@
+saul_drivers
+============
+
+This application is only used by the CI to check the build of drivers that
+provide a SAUL interface.
+All such drivers are added automatically to the build along with the
+`saul_default` module. This will check:
+- the build of the saul interface,
+- the build of driver auto initialization.

tests/saul_drivers/main.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2022 Inria
+ *
+ * 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       Build test application for drivers providing a SAUL interface
+ *
+ * @author      Alexandre Abadie <alexandre.abadie@inria.fr>
+ *
+ * @}
+ */
+
+int main(void)
+{
+    return 0;
+}