assertTrue(Files.isDirectory(nestedPath));
        } finally {
            // Cleanup
            deleteDirectory(tempDir.toFile());
        }
    }

    @Test
    public void test_createDirectories_existingPath() throws Exception {
        // Test that Files.createDirectories is idempotent (no exception on existing dir)
        Path tempDir = Files.createTempDirectory("toctou_test");
        try {