tests: subsys: fs: Add FSTAB_ENTRY_DT_*_MOUNT_POINT unit test

Add unit tests for `FSTAB_ENTRY_DT_MOUNT_POINT`
and `FSTAB_ENTRY_DT_INST_MOUNT_POINT` macros.

Signed-off-by: James Roy <[email protected]>

Author: rruuaanng

tests/subsys/fs/fs_api/app.overlay

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: Apache-2.0
+
+/ {
+	test_disk: disk {
+		compatible = "zephyr,fstab,fatfs";
+		mount-point = "/TEST:";
+	};
+};

tests/subsys/fs/fs_api/src/test_fs_dt.c

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 James Roy <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT zephyr_fstab_fatfs
+#include "test_fs.h"
+
+#define TEST_NODELABEL DT_NODELABEL(test_disk)
+
+ZTEST(test_fs_dt_api, test_dt_api_mount_point)
+{
+	const char *mnt_point1, *mnt_point2;
+
+	mnt_point1 = FSTAB_ENTRY_DT_MOUNT_POINT(TEST_NODELABEL);
+	zassert_str_equal(mnt_point1, "/TEST:");
+
+	mnt_point2 = FSTAB_ENTRY_DT_INST_MOUNT_POINT(0);
+	zassert_str_equal(mnt_point2, "/TEST:");
+}
+
+ZTEST_SUITE(test_fs_dt_api, NULL, NULL, NULL, NULL, NULL);