test: rng: Add basic test for random number generator(rng) uclass

Add a unit test for testing the rng uclass functionality using the
sandbox rng driver.
Signed-off-by: NSughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: NPatrice Chotard <patrice.chotard@st.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

test/dm/Makefile

@@ -68,4 +68,5 @@ obj-$(CONFIG_VIRTIO_SANDBOX) += virtio.o
 obj-$(CONFIG_DMA) += dma.o
 obj-$(CONFIG_DM_MDIO) += mdio.o
 obj-$(CONFIG_DM_MDIO_MUX) += mdio_mux.o
+obj-$(CONFIG_DM_RNG) += rng.o
 endif

test/dm/rng.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+/* Basic test of the rng uclass */
+static int dm_test_rng_read(struct unit_test_state *uts)
+{
+	unsigned long rand1 = 0, rand2 = 0;
+	struct udevice *dev;
+
+	ut_assertok(uclass_get_device(UCLASS_RNG, 0, &dev));
+	ut_assertnonnull(dev);
+	ut_assertok(dm_rng_read(dev, &rand1, sizeof(rand1)));
+	ut_assertok(dm_rng_read(dev, &rand2, sizeof(rand2)));
+	ut_assert(rand1 != rand2);
+
+	return 0;
+}
+DM_TEST(dm_test_rng_read, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);