tests: posix: add testsuite for POSIX_FILE_LOCKING Option Group

Add a testsuite for the POSIX_FILE_LOCKING Option Group.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

Author: cfriedt

tests/posix/file_locking/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(posix_file_locking)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})
+
+target_compile_options(app PRIVATE -U_POSIX_C_SOURCE -D_POSIX_C_SOURCE=200809L)

tests/posix/file_locking/Kconfig

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+# Copyright (c) 2024 Tenstorrent AI ULC
+# SPDX-License-Identifier: Apache-2.0
+
+source "Kconfig.zephyr"
+
+menu "File Locking Tests"
+
+config TEST_NEGLIGIBLE_DELAY_MS
+	int "Negligible delay in milliseconds"
+	default 10
+	help
+	  Delays less than or equal to this value are considered neglible for the purposes of this
+	  testsuite.
+
+config TEST_LOCK_PERIOD_MS
+	int "Time to hold a lock in milliseconds"
+	default 100
+	help
+	  The amount of time to hold a lock before releasing it, for the purposes of this testuite.
+
+endmenu

tests/posix/file_locking/app.overlay

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+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	ramdisk0 {
+		compatible = "zephyr,ram-disk";
+		disk-name = "RAM";
+		sector-size = <512>;
+		sector-count = <160>;
+	};
+};

tests/posix/file_locking/prj.conf

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+CONFIG_POSIX_API=y
+CONFIG_ZTEST=y
+
+CONFIG_POSIX_AEP_CHOICE_BASE=y
+CONFIG_POSIX_FILE_LOCKING=y
+CONFIG_FAT_FILESYSTEM_ELM=y
+
+# pthreads are used for simplicity here, although that isn't strictly necessary
+CONFIG_THREAD_STACK_INFO=y
+CONFIG_DYNAMIC_THREAD=y
+CONFIG_DYNAMIC_THREAD_POOL_SIZE=4
+
+CONFIG_MAIN_STACK_SIZE=4096

tests/posix/file_locking/src/fs.c

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+/*
+ * Copyright (c) 2024 Tenstorrent AI ULC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <ff.h>
+#include <zephyr/fs/fs.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/ztest.h>
+
+static FATFS _fs;
+
+static struct fs_mount_t _mnt = {
+	.type = FS_FATFS,
+	.mnt_point = "/",
+	.fs_data = &_fs,
+};
+
+struct _entry {
+	const char *const name;
+	const char *const data;
+	FILE *fp;
+};
+
+static struct _entry _data[] = {
+	{.name = "/tmp/foo.txt", .data = ""},
+	{.name = "/tmp/bar.txt", .data = ""},
+};
+
+void setup_callback(void *arg);
+void before_callback(void *arg);
+void after_callback(void *arg);
+
+void *setup(void)
+{
+	int ret;
+
+	memset(&_fs, 0, sizeof(_fs));
+
+	ret = fs_mount(&_mnt);
+	zassert_ok(ret, "mount failed: %d", ret);
+
+	ret = fs_mkdir("/tmp");
+	zassert_ok(ret, "mkdir failed: %d", ret);
+
+	setup_callback(NULL);
+
+	return NULL;
+}
+
+void before(void *arg)
+{
+	ARG_UNUSED(arg);
+
+	ARRAY_FOR_EACH_PTR(_data, entry) {
+		int len;
+		int ret;
+
+		entry->fp = fopen(entry->name, "w+");
+		zassert_not_null(entry->fp, "fopen() failed: %d", errno);
+
+		len = strlen(entry->data);
+		if (len > 0) {
+			ret = (int)fwrite(entry->data, len, 1, entry->fp);
+			zassert_equal(ret, len, "%s returned %d instead of %d: %d", "fwrite", ret,
+				      len, errno);
+		}
+
+		before_callback(entry->fp);
+	};
+}
+
+void after(void *arg)
+{
+	ARG_UNUSED(arg);
+
+	ARRAY_FOR_EACH_PTR(_data, entry) {
+		(void)fclose(entry->fp);
+	};
+
+	after_callback(NULL);
+}
+
+void teardown(void *arg)
+{
+	ARG_UNUSED(arg);
+	(void)fs_unmount(&_mnt);
+}