tests: bluetooth: buf: Test the freed buf callback

This commit adds a unit test that checks the freed buffer callback of
the bluetooth data buffer API.

Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>

tests/bluetooth/buf/CMakeLists.txt

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(buf)
+
+target_sources(app PRIVATE src/main.c)

tests/bluetooth/buf/prj.conf

@@ -0,0 +1,10 @@
+CONFIG_TEST=y
+CONFIG_ZTEST=y
+
+CONFIG_BT=y
+CONFIG_BT_CTLR=n
+CONFIG_BT_H4=n
+
+# Needed to enable and test the iso rx pool
+CONFIG_BT_OBSERVER=y
+CONFIG_BT_ISO_SYNC_RECEIVER=y

tests/bluetooth/buf/src/main.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+
+#include <errno.h>
+#include <zephyr/tc_util.h>
+#include <zephyr/ztest.h>
+
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/bluetooth/buf.h>
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/drivers/bluetooth.h>
+#include <zephyr/sys/byteorder.h>
+
+static enum bt_buf_type freed_buf_type;
+static K_SEM_DEFINE(rx_sem, 0, 1);
+
+void bt_buf_rx_freed_cb(enum bt_buf_type type)
+{
+	freed_buf_type = type;
+	k_sem_give(&rx_sem);
+}
+
+ZTEST_SUITE(test_buf_data_api, NULL, NULL, NULL, NULL, NULL);
+
+ZTEST(test_buf_data_api, test_buf_freed_cb)
+{
+	struct net_buf *buf;
+	int err;
+
+	bt_buf_rx_freed_cb_set(bt_buf_rx_freed_cb);
+
+	/* Test that the callback is called for the BT_BUF_EVT type */
+	buf = bt_buf_get_rx(BT_BUF_EVT, K_NO_WAIT);
+	zassert_not_null(buf, "Failed to get event buffer");
+
+	net_buf_unref(buf);
+	/* The freed buf cb is called from net_buf_unref, therefore the semaphore should
+	 * already by given.
+	 */
+	err = k_sem_take(&rx_sem, K_NO_WAIT);
+	zassert_equal(err, 0, "Timeout while waiting for event buffer to be freed");
+	zassert_equal(BT_BUF_EVT, BT_BUF_EVT & freed_buf_type, "Event buffer wasn't freed");
+
+	/* Test that the callback is called for the BT_BUF_ACL_IN type */
+	buf = bt_buf_get_rx(BT_BUF_ACL_IN, K_NO_WAIT);
+	zassert_not_null(buf, "Failed to get ACL buffer");
+
+	net_buf_unref(buf);
+	/* The freed buf cb is called from net_buf_unref, therefore the semaphore should
+	 * already by given.
+	 */
+	err = k_sem_take(&rx_sem, K_NO_WAIT);
+	zassert_equal(err, 0, "Timeout while waiting for ACL buffer to be freed");
+	zassert_equal(BT_BUF_ACL_IN, BT_BUF_ACL_IN & freed_buf_type, "ACL buffer wasn't freed");
+
+	/* Test that the callback is called for the BT_BUF_ISO_IN type */
+	buf = bt_buf_get_rx(BT_BUF_ISO_IN, K_NO_WAIT);
+	zassert_not_null(buf, "Failed to get ISO buffer");
+
+	net_buf_unref(buf);
+	/* The freed buf cb is called from net_buf_unref, therefore the semaphore should
+	 * already by given.
+	 */
+	err = k_sem_take(&rx_sem, K_NO_WAIT);
+	zassert_equal(err, 0, "Timeout while waiting for ISO buffer to be freed");
+	zassert_equal(BT_BUF_ISO_IN, BT_BUF_ISO_IN & freed_buf_type, "ISO buffer wasn't freed");
+}

tests/bluetooth/buf/testcase.yaml

@@ -0,0 +1,30 @@
+common:
+  tags:
+    - bluetooth
+    - host
+
+tests:
+  bluetooth.buf:
+    platform_allow:
+      - native_sim
+      - native_sim/native/64
+    integration_platforms:
+      - native_sim
+    extra_configs:
+      - CONFIG_BT_HCI_ACL_FLOW_CONTROL=y
+  bluetooth.buf.no_acl_flow_control:
+    platform_allow:
+      - native_sim
+      - native_sim/native/64
+    integration_platforms:
+      - native_sim
+    extra_configs:
+      - CONFIG_BT_HCI_ACL_FLOW_CONTROL=n
+  bluetooth.buf.hci_raw:
+    platform_allow:
+      - native_sim
+      - native_sim/native/64
+    integration_platforms:
+      - native_sim
+    extra_configs:
+      - CONFIG_BT_HCI_RAW=y