Industry Coding Practice Framework

This project simulates a CodeSignal Industry Coding Framework assessment. It contains four progressive coding levels that build on each other, similar to a real industry OA environment.

---

🧭 Structure

industry_coding_practice/
│
├── level1_basic.py
├── level2_processing.py
├── level3_refactor.py
├── level4_extend.py
│
├── test_level1.py
├── test_level2.py
├── test_level3.py
├── test_level4.py
│
└── README.md

Each level has:

• A starter implementation file (levelX_*.py) with function headers, docstrings, and # TODO markers.
• A corresponding test file (test_levelX.py) that you can run directly with Python.

---

⚙️ How to Run

1. Implement the TODOs for the current level.

2. Run tests for that level using:

   python test_level1.py

3. Move to the next level and repeat the process.

---

🧩 Levels and Evaluation Criteria

Level 1 – Initial Design & Basic Functions

Focus: General programming skills, basic data structures, and error handling.

You must implement:

• FILE_UPLOAD(file_name, size)
  Upload file to the server. Raise RuntimeError if file exists.
• FILE_GET(file_name)
  Return size if exists, else None.
• FILE_COPY(source, dest)
  Copy a file. Raise error if source missing. Overwrite destination if exists.

Skills Tested:

• Control flow
• Dictionaries/lists
• Error handling

---

Level 2 – Data Structures & Data Processing

Focus: Data manipulation, searching, and sorting.

New method:

• FILE_SEARCH(prefix)
  Return up to 10 files starting with prefix. Sort by:
  1. Size (descending)
  2. File name (ascending)

Skills Tested:

• Sorting by multiple criteria
• Filtering data
• Building on existing methods

---

Level 3 – Refactoring & Encapsulation

Focus: Time-dependent data, encapsulation, and TTL handling.

New methods:

• FILE_UPLOAD_AT(timestamp, file_name, file_size, ttl=None)
  Upload a file with an optional time-to-live (seconds). If a file is created with timestamp 10 and ttl 5, at timestamp 15 it is expired.
• FILE_GET_AT(timestamp, file_name)
  Return file size only if file is still alive at timestamp.
• FILE_COPY_AT(timestamp, source, dest)
  Copy a file only if it exists and is alive.
• FILE_SEARCH_AT(timestamp, prefix)
  Search only for alive files.

Skills Tested:

• Time-based logic
• Conditional filtering
• Code reuse and refactoring

---

Level 4 – Extending Design & Functionality

Focus: System rollback and code scalability.

New method:

• ROLLBACK(timestamp)
  Restore the system to its state at the given timestamp.

Skills Tested:

• State reconstruction
• System design thinking
• Maintaining backward compatibility

---

🧠 Tips for Practice

• Work level by level — don’t skip ahead.
• Aim for clean, reusable code at each step.
• You can print your outputs while debugging; final tests should pass silently.

---

Good luck and have fun practicing!