tests: zbus: add shadow channel test suite

Add test suite to verify the shadow channel functionality when
CONFIG_ZBUS_MULTIDOMAIN is enabled.

Signed-off-by: Trond F. Christiansen <[email protected]>

Author: Trond-F-Christiansen

tests/subsys/zbus/shadow_channels/CMakeLists.txt

@@ -0,0 +1,13 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(test_shadow_channels)
+
+FILE(GLOB app_sources src/main.c)
+target_sources(app PRIVATE ${app_sources})

tests/subsys/zbus/shadow_channels/prj.conf

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+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+CONFIG_ZTEST=y
+CONFIG_ASSERT=n
+CONFIG_LOG=y
+CONFIG_CRC=y
+CONFIG_ZBUS=y
+CONFIG_ZBUS_CHANNEL_ID=y
+CONFIG_ZBUS_CHANNEL_NAME=y
+CONFIG_ZBUS_MSG_SUBSCRIBER=y
+CONFIG_ZBUS_MULTIDOMAIN=y

tests/subsys/zbus/shadow_channels/src/main.c

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+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/zbus/zbus.h>
+#include <zephyr/ztest.h>
+#include <zephyr/ztest_assert.h>
+
+struct msg {
+	int x;
+};
+
+enum channel_ids {
+	CHAN_B = 123,
+	CHAN_D = 125,
+};
+
+/* Normal channels */
+ZBUS_CHAN_DEFINE(chan_a, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY, ZBUS_MSG_INIT(0));
+ZBUS_CHAN_DEFINE_WITH_ID(chan_b, CHAN_B, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY,
+			 ZBUS_MSG_INIT(0));
+
+/* Shadow channels */
+ZBUS_SHADOW_CHAN_DEFINE(chan_c, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY, ZBUS_MSG_INIT(0));
+ZBUS_SHADOW_CHAN_DEFINE_WITH_ID(chan_d, CHAN_D, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY,
+				ZBUS_MSG_INIT(0));
+
+/* Multidomain channels */
+ZBUS_MULTIDOMAIN_CHAN_DEFINE(chan_e, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY, ZBUS_MSG_INIT(0),
+			     true, true);
+ZBUS_MULTIDOMAIN_CHAN_DEFINE(chan_f, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY, ZBUS_MSG_INIT(0),
+			     false, true);
+ZBUS_MULTIDOMAIN_CHAN_DEFINE(chan_g, struct msg, NULL, NULL, ZBUS_OBSERVERS_EMPTY, ZBUS_MSG_INIT(0),
+			     false, false);
+
+ZTEST(shadow_channels, test_shadow_channel_identification)
+{
+	/* Check shadow channel identification */
+	zassert_false(ZBUS_CHANNEL_IS_SHADOW(&chan_a));
+	zassert_false(ZBUS_CHANNEL_IS_SHADOW(&chan_b));
+
+	zassert_true(ZBUS_CHANNEL_IS_SHADOW(&chan_c));
+	zassert_true(ZBUS_CHANNEL_IS_SHADOW(&chan_d));
+
+	zassert_false(ZBUS_CHANNEL_IS_SHADOW(&chan_e));
+	zassert_true(ZBUS_CHANNEL_IS_SHADOW(&chan_f));
+
+	/* Check master channel identification */
+	zassert_true(ZBUS_CHANNEL_IS_MASTER(&chan_a));
+	zassert_true(ZBUS_CHANNEL_IS_MASTER(&chan_b));
+
+	zassert_false(ZBUS_CHANNEL_IS_MASTER(&chan_c));
+	zassert_false(ZBUS_CHANNEL_IS_MASTER(&chan_d));
+
+	zassert_true(ZBUS_CHANNEL_IS_MASTER(&chan_e));
+	zassert_false(ZBUS_CHANNEL_IS_MASTER(&chan_f));
+}
+
+ZTEST(shadow_channels, test_shadow_channel_exclusion)
+{
+	/* NOTE: chan_g should not be defined as _is_included in the macro is false
+	 * Therefore, zbus_chan_from_name("chan_g") should return NULL
+	 */
+	zassert_is_null(zbus_chan_from_name("chan_g"));
+}
+
+ZTEST(shadow_channels, test_pub)
+{
+	struct msg msg = {42};
+
+	/* normal publish cannot be used on shadow channels */
+	zassert_equal(-EPERM, zbus_chan_pub(&chan_c, &msg, K_NO_WAIT));
+	zassert_equal(-EPERM, zbus_chan_pub(&chan_d, &msg, K_NO_WAIT));
+	zassert_equal(-EPERM, zbus_chan_pub(&chan_f, &msg, K_NO_WAIT));
+
+	/* shadow publish can be used on shadow channels */
+	zassert_equal(0, zbus_chan_pub_shadow(&chan_c, &msg, K_NO_WAIT));
+	zassert_equal(0, zbus_chan_pub_shadow(&chan_d, &msg, K_NO_WAIT));
+	zassert_equal(0, zbus_chan_pub_shadow(&chan_f, &msg, K_NO_WAIT));
+
+	/* shadow publish cannot be used on normal channels */
+	zassert_equal(-EPERM, zbus_chan_pub_shadow(&chan_a, NULL, K_NO_WAIT));
+	zassert_equal(-EPERM, zbus_chan_pub_shadow(&chan_b, NULL, K_NO_WAIT));
+	zassert_equal(-EPERM, zbus_chan_pub_shadow(&chan_e, NULL, K_NO_WAIT));
+}
+
+ZTEST_SUITE(shadow_channels, NULL, NULL, NULL, NULL, NULL);

tests/subsys/zbus/shadow_channels/testcase.yaml

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+tests:
+  message_bus.zbus.shadow_channels:
+    tags: zbus
+    integration_platforms:
+      - native_sim