unittests: Provide unittests for net_dev_dummy

* tests if net_dev_dummy is correct and if driver part of net_dev is
  correct

tests/unittests/tests-netdev_dummy/Makefile

@@ -0,0 +1,26 @@
+MODULE = tests-netdev_dummy
+
+RANDOM_8BIT = $(shell od -vAn -N1 -td1 < /dev/urandom | xargs echo)
+RANDOM_16BIT = $(shell od -vAn -N2 -td2 < /dev/urandom | xargs echo)
+RANDOM_32BIT = $(shell od -vAn -N4 -td4 < /dev/urandom | xargs echo)
+RANDOM_64BIT = $(shell od -vAn -N8 -td8 < /dev/urandom | xargs echo)
+RANDOM_U8BIT = $(shell od -vAn -N1 -tu1 < /dev/urandom | xargs echo)
+RANDOM_U16BIT = $(shell od -vAn -N2 -tu2 < /dev/urandom | xargs echo)
+RANDOM_U32BIT = $(shell od -vAn -N4 -tu4 < /dev/urandom | xargs echo)
+RANDOM_U64BIT = $(shell od -vAn -N8 -tu8 < /dev/urandom | xargs echo)
+RANDOM_STRING = "$(shell head -c "$(1)" /dev/urandom | base64 | head -c "$(1)")"
+
+include $(RIOTBASE)/Makefile.base
+
+CFLAGS += -DRAND_STRING8="\"$(call RANDOM_STRING,8)\""
+CFLAGS += -DRAND_STRING12="\"$(call RANDOM_STRING,12)\""
+CFLAGS += -DRAND_STRING16="\"$(call RANDOM_STRING,16)\""
+CFLAGS += -DRAND_STRING64="\"$(call RANDOM_STRING,64)\""
+CFLAGS += -DRAND_INT8=$(RANDOM_8BIT)
+CFLAGS += -DRAND_INT16=$(RANDOM_16BIT)
+CFLAGS += -DRAND_INT32=$(RANDOM_32BIT)
+CFLAGS += -DRAND_INT64=$(RANDOM_64BIT)
+CFLAGS += -DRAND_UINT8=$(RANDOM_U8BIT)U
+CFLAGS += -DRAND_UINT16=$(RANDOM_U16BIT)U
+CFLAGS += -DRAND_UINT32=$(RANDOM_U32BIT)U
+CFLAGS += -DRAND_UINT64=$(RANDOM_U64BIT)U

tests/unittests/tests-netdev_dummy/Makefile.include

@@ -0,0 +1 @@
+USEMODULE += netdev_dummy