Please use FileSystem tools to finish the following task:

### Task Description

You are given a directory containing multiple text files of varying sizes. Your task is to identify the 10 smallest .txt files, merge their content in alphabetical order, and create a consolidated file called "merged_content.txt" with proper formatting.

### Task Objectives

1. **Identify the 10 smallest .txt files** in the test directory
2. **Sort the selected files alphabetically** by filename
3. **Merge the content** of these files into a single file
4. **Add file headers** (file name) before each file's content
