Bluetooth: Host: Add a test for connection creation timeout

It seemed like there was lacking test coverage for this
functionality.

Signed-off-by: Rubin Gerritsen <rubin.gerritsen@nordicsemi.no>

tests/bsim/bluetooth/host/central/CMakeLists.txt

@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(central)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources} )
+
+# This contains babblesim-specific helpers, e.g. device synchronization.
+add_subdirectory(${ZEPHYR_BASE}/tests/bsim/babblekit babblekit)
+target_link_libraries(app PRIVATE babblekit)
+
+zephyr_include_directories(
+  ${BSIM_COMPONENTS_PATH}/libUtilv1/src/
+  ${BSIM_COMPONENTS_PATH}/libPhyComv1/src/
+  )
+
+add_subdirectory(${ZEPHYR_BASE}/tests/bluetooth/common/testlib testlib)
+target_link_libraries(app PRIVATE
+  testlib
+)

tests/bsim/bluetooth/host/central/prj.conf

@@ -0,0 +1,3 @@
+CONFIG_ASSERT=y
+CONFIG_BT=y
+CONFIG_BT_CENTRAL=y

tests/bsim/bluetooth/host/central/src/main.c

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "bstests.h"
+#include "babblekit/testcase.h"
+#include <zephyr/bluetooth/conn.h>
+
+static K_SEM_DEFINE(sem_connected, 0, 1);
+
+static void connected_cb(struct bt_conn *conn, uint8_t err)
+{
+	TEST_ASSERT(conn);
+	TEST_ASSERT(err == BT_HCI_ERR_UNKNOWN_CONN_ID, "Expected connection timeout");
+
+	k_sem_give(&sem_connected);
+	bt_conn_unref(conn);
+}
+
+static struct bt_conn_cb conn_cb = {
+	.connected = connected_cb,
+};
+
+static void test_central_connect_timeout_with_timeout(uint32_t timeout_ms)
+{
+	int err;
+	struct bt_conn *conn;
+
+	/* A zero value for `bt_conn_le_create_param.timeout` shall be
+	 * interpreted as `CONFIG_BT_CREATE_CONN_TIMEOUT`.
+	 */
+	uint32_t expected_conn_timeout_ms =
+		timeout_ms ? timeout_ms : CONFIG_BT_CREATE_CONN_TIMEOUT * MSEC_PER_SEC;
+
+	bt_addr_le_t peer = {.a.val = {0x01}};
+	const struct bt_conn_le_create_param create_param = {
+		.options = BT_CONN_LE_OPT_NONE,
+		.interval = BT_GAP_SCAN_FAST_INTERVAL,
+		.window = BT_GAP_SCAN_FAST_WINDOW,
+		.interval_coded = 0,
+		.window_coded = 0,
+		.timeout = timeout_ms / 10,
+	};
+
+	k_sem_reset(&sem_connected);
+
+	const uint64_t conn_create_start = k_uptime_get();
+
+	err = bt_conn_le_create(&peer, &create_param, BT_LE_CONN_PARAM_DEFAULT, &conn);
+	TEST_ASSERT(err == 0, "Failed starting initiator (err %d)", err);
+
+	err = k_sem_take(&sem_connected, K_MSEC(2 * expected_conn_timeout_ms));
+	TEST_ASSERT(err == 0, "Failed getting connected timeout within %d s (err %d)",
+		    2 * expected_conn_timeout_ms, err);
+
+	const uint64_t conn_create_end = k_uptime_get();
+
+	const int64_t time_diff_ms = conn_create_end - conn_create_start;
+	const int64_t diff_to_expected_ms = abs(time_diff_ms - expected_conn_timeout_ms);
+
+	TEST_PRINT("Connection timeout after %d ms", time_diff_ms);
+	TEST_ASSERT(diff_to_expected_ms < 0.1 * expected_conn_timeout_ms,
+		    "Connection timeout not within 10%% of expected timeout. "
+		    "Actual timeout: %d", time_diff_ms);
+}
+
+static void test_central_connect_timeout(void)
+{
+	int err;
+
+	bt_conn_cb_register(&conn_cb);
+
+	/* Initialize Bluetooth */
+	err = bt_enable(NULL);
+	TEST_ASSERT(err == 0, "Can't enable Bluetooth (err %d)", err);
+
+	test_central_connect_timeout_with_timeout(0);
+	test_central_connect_timeout_with_timeout(1000);
+
+	TEST_PASS("Correct timeout");
+}
+
+static const struct bst_test_instance test_def[] = {
+	{
+		.test_id = "central_connect_timeout",
+		.test_descr = "Verifies that the default connection timeout is used correctly",
+		.test_tick_f = bst_tick,
+		.test_main_f = test_central_connect_timeout
+	},
+	BSTEST_END_MARKER
+};
+
+static struct bst_test_list *test_central_install(struct bst_test_list *tests)
+{
+	return bst_add_tests(tests, test_def);
+}
+
+bst_test_install_t test_installers[] = {
+	test_central_install,
+	NULL
+};
+
+int main(void)
+{
+	bst_main();
+	return 0;
+}

tests/bsim/bluetooth/host/central/tests_scripts/_compile.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# Copyright 2024 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+set -eu
+: "${ZEPHYR_BASE:?ZEPHYR_BASE must be defined}"
+
+INCR_BUILD=1
+
+source ${ZEPHYR_BASE}/tests/bsim/compile.source
+
+app="$(guess_test_relpath)" compile
+
+wait_for_background_jobs

tests/bsim/bluetooth/host/central/tests_scripts/run_central_connect_timeout.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Copyright (c) 2024 Nordic Semiconductor
+# SPDX-License-Identifier: Apache-2.0
+
+source ${ZEPHYR_BASE}/tests/bsim/sh_common.source
+
+simulation_id="central_connect_timeout"
+verbosity_level=2
+
+cd ${BSIM_OUT_PATH}/bin
+
+Execute ./bs_${BOARD_TS}_tests_bsim_bluetooth_host_central_prj_conf \
+  -v=${verbosity_level} -s=${simulation_id} -d=0 -testid=central_connect_timeout
+
+Execute ./bs_2G4_phy_v1 -v=${verbosity_level} -s=${simulation_id} \
+  -D=1 -sim_length=60e6 $@
+
+wait_for_background_jobs

tests/bsim/bluetooth/host/compile.sh

@@ -12,6 +12,7 @@ set -ue
 source ${ZEPHYR_BASE}/tests/bsim/compile.source
 
 ${ZEPHYR_BASE}/tests/bsim/bluetooth/host/adv/compile.sh
+app=tests/bsim/bluetooth/host/central compile
 ${ZEPHYR_BASE}/tests/bsim/bluetooth/host/att/compile.sh
 ${ZEPHYR_BASE}/tests/bsim/bluetooth/host/gatt/compile.sh
 ${ZEPHYR_BASE}/tests/bsim/bluetooth/host/l2cap/compile.sh