test/dm: check if devices exist

Running 'ut dm' on the sandbox without -D or -d results in segmentation
faults due to NULL pointer dereferences.

Check that device pointers are non-NULL before using them.

Use ut_assertnonnull() for pointers instead of ut_assert().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/test/dm/acpi.c b/test/dm/acpi.c
index b94c4ba..bb8550f 100644
--- a/test/dm/acpi.c
+++ b/test/dm/acpi.c
@@ -190,7 +190,10 @@
 static int dm_test_acpi_create_dmar(struct unit_test_state *uts)
 {
 	struct acpi_dmar dmar;
+	struct udevice *cpu;
 
+	ut_assertok(uclass_first_device(UCLASS_CPU, &cpu));
+	ut_assertnonnull(cpu);
 	ut_assertok(acpi_create_dmar(&dmar, DMAR_INTR_REMAP));
 	ut_asserteq(DMAR_INTR_REMAP, dmar.flags);
 	ut_asserteq(32 - 1, dmar.host_address_width);
diff --git a/test/dm/core.c b/test/dm/core.c
index 6a930ae..d20c484 100644
--- a/test/dm/core.c
+++ b/test/dm/core.c
@@ -158,7 +158,7 @@
 	for (uclass_find_first_device(UCLASS_TEST, &dev);
 	     dev;
 	     uclass_find_next_device(&dev)) {
-		ut_assert(dev);
+		ut_assertnonnull(dev);
 
 		uc_pdata = dev_get_uclass_platdata(dev);
 		ut_assert(uc_pdata);
@@ -181,7 +181,7 @@
 	for (uclass_find_first_device(UCLASS_TEST, &dev);
 	     dev;
 	     uclass_find_next_device(&dev)) {
-		ut_assert(dev);
+		ut_assertnonnull(dev);
 
 		uc_pdata = dev_get_uclass_platdata(dev);
 		ut_assert(uc_pdata);
@@ -747,11 +747,11 @@
 	     dev;
 	     ret = uclass_find_next_device(&dev)) {
 		ut_assert(!ret);
-		ut_assert(dev);
+		ut_assertnonnull(dev);
 	}
 
 	ut_assertok(uclass_find_first_device(UCLASS_TEST_DUMMY, &dev));
-	ut_assert(!dev);
+	ut_assertnull(dev);
 
 	return 0;
 }
@@ -778,7 +778,7 @@
 	     testdev;
 	     ret = uclass_find_next_device(&testdev)) {
 		ut_assertok(ret);
-		ut_assert(testdev);
+		ut_assertnonnull(testdev);
 
 		findret = uclass_find_device_by_name(UCLASS_TEST_FDT,
 						     testdev->name,
diff --git a/test/dm/devres.c b/test/dm/devres.c
index b5de0cb..5507874 100644
--- a/test/dm/devres.c
+++ b/test/dm/devres.c
@@ -153,6 +153,7 @@
 	 * allocation created in the bind() method.
 	 */
 	ut_assertok(uclass_find_first_device(UCLASS_TEST_DEVRES, &dev));
+	ut_assertnonnull(dev);
 	devres_get_stats(dev, &stats);
 	ut_asserteq(1, stats.allocs);
 	ut_asserteq(TEST_DEVRES_SIZE, stats.total_size);
diff --git a/test/dm/test-fdt.c b/test/dm/test-fdt.c
index 51f2547..8ef7c7a 100644
--- a/test/dm/test-fdt.c
+++ b/test/dm/test-fdt.c
@@ -832,10 +832,12 @@
 	struct udevice *back, *dev, *dev2;
 
 	ut_assertok(uclass_find_first_device(UCLASS_PANEL_BACKLIGHT, &back));
+	ut_assertnonnull(back);
 	ut_asserteq(-ENOENT, uclass_find_device_by_phandle(UCLASS_REGULATOR,
 							back, "missing", &dev));
 	ut_assertok(uclass_find_device_by_phandle(UCLASS_REGULATOR, back,
 						  "power-supply", &dev));
+	ut_assertnonnull(dev);
 	ut_asserteq(0, device_active(dev));
 	ut_asserteq_str("ldo1", dev->name);
 	ut_assertok(uclass_get_device_by_phandle(UCLASS_REGULATOR, back,
diff --git a/test/dm/virtio.c b/test/dm/virtio.c
index 4b317d2..4a0c0b2 100644
--- a/test/dm/virtio.c
+++ b/test/dm/virtio.c
@@ -22,9 +22,11 @@
 
 	/* check probe success */
 	ut_assertok(uclass_first_device(UCLASS_VIRTIO, &bus));
+	ut_assertnonnull(bus);
 
 	/* check the child virtio-blk device is bound */
 	ut_assertok(device_find_first_child(bus, &dev));
+	ut_assertnonnull(dev);
 	ut_assertok(strcmp(dev->name, "virtio-blk#0"));
 
 	/* check driver status */
@@ -49,15 +51,18 @@
 
 	/* check probe success */
 	ut_assertok(uclass_first_device(UCLASS_VIRTIO, &bus));
+	ut_assertnonnull(bus);
 
 	/* check the child virtio-blk device is bound */
 	ut_assertok(device_find_first_child(bus, &dev));
+	ut_assertnonnull(dev);
 
 	/*
 	 * fake the virtio device probe by filling in uc_priv->vdev
 	 * which is used by virtio_find_vqs/virtio_del_vqs.
 	 */
 	uc_priv = dev_get_uclass_priv(bus);
+	ut_assertnonnull(uc_priv);
 	uc_priv->vdev = dev;
 
 	/* test virtio_xxx APIs */
@@ -106,9 +111,11 @@
 
 	/* check probe success */
 	ut_assertok(uclass_first_device(UCLASS_VIRTIO, &bus));
+	ut_assertnonnull(bus);
 
 	/* check the child virtio-blk device is bound */
 	ut_assertok(device_find_first_child(bus, &dev));
+	ut_assertnonnull(dev);
 
 	/* set driver status to VIRTIO_CONFIG_S_DRIVER_OK */
 	ut_assertok(virtio_set_status(dev, VIRTIO_CONFIG_S_DRIVER_OK));