Please use FileSystem tools to finish the following task:

### Task Description

You need to process 10 text files (file_01.txt to file_10.txt) and convert their content to uppercase format.

### Task Objectives

1. **Create an uppercase directory** in the test environment root
2. **Convert each file** from file_01.txt to file_10.txt to uppercase
3. **Save converted files** in the uppercase/ directory with the same names
4. **Count words** in each original file (file_01.txt to file_10.txt)
5. **Create answer.txt** with word counts in the specified format.

### Specified Format of answer.txt

Create a file named `answer.txt` in uppercase/

**Requirements:**

- Each line should follow the format: `<filename>:<word_count>`
- Include all 10 files: file_01.txt, file_02.txt, ..., file_10.txt
- Use the exact filename format (file_01.txt, file_02.txt, etc.)
- One entry per line
