firewire: test: add KUnit test for device attributes

The traverse over CSR space results in attributes of node and unit
devices. Any test of the traverse is useful.

This commit adds a skeleton of KUnit test for the purpose.

Link: https://lore.kernel.org/r/20231221134849.603857-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/firewire/.kunitconfig

@@ -2,3 +2,4 @@ CONFIG_KUNIT=y
 CONFIG_PCI=y
 CONFIG_FIREWIRE=y
 CONFIG_FIREWIRE_KUNIT_UAPI_TEST=y
+CONFIG_FIREWIRE_KUNIT_DEVICE_ATTRIBUTE_TEST=y

drivers/firewire/Kconfig

@@ -34,6 +34,22 @@ config FIREWIRE_KUNIT_UAPI_TEST
 	  For more information on KUnit and unit tests in general, refer
 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
 
+config FIREWIRE_KUNIT_DEVICE_ATTRIBUTE_TEST
+	tristate "KUnit tests for device attributes" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests for device attribute for node and
+	  unit.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
 config FIREWIRE_OHCI
 	tristate "OHCI-1394 controllers"
 	depends on PCI && FIREWIRE && MMU

drivers/firewire/core-device.c

@@ -1310,3 +1310,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 		break;
 	}
 }
+
+#ifdef CONFIG_FIREWIRE_KUNIT_DEVICE_ATTRIBUTE_TEST
+#include "device-attribute-test.c"
+#endif

drivers/firewire/device-attribute-test.c

+// SPDX-License-Identifier: GPL-2.0-only
+//
+// device-attribute-test.c - An application of Kunit to test implementation for device attributes.
+//
+// Copyright (c) 2023 Takashi Sakamoto
+//
+// This file can not be built independently since it is intentionally included in core-device.c.
+
+#include <kunit/test.h>
+
+static struct kunit_case device_attr_test_cases[] = {
+	{}
+};
+
+static struct kunit_suite device_attr_test_suite = {
+	.name = "firewire-device-attribute",
+	.test_cases = device_attr_test_cases,
+};
+kunit_test_suite(device_attr_test_suite);