# Roman numerals converter

Original assessment brief: https://github.com/turner-townsend/backend-assessment/blob/master/README.md#roman-numerals

A simple Python program that converts Roman numerals to Arabic numbers using additive logic.

## Supported numerals

| Numeral | Value |
| ------- | ----- |
| I       | 1     |
| V       | 5     |
| X       | 10    |
| C       | 100   |
| M       | 1000  |

## Usage

```bash
python roman.py
```

### Examples

```
Please enter some Roman numerals: I
I = 1

Please enter some Roman numerals: VI
VI = 5 + 1 = 6

Please enter some Roman numerals: MXVII
MXVII = 1000 + 10 + 5 + 1 + 1 = 1017

Please enter some Roman numerals: ABC
ERROR: Invalid input
```

## Features

- **Additive conversion**: Treats all numerals as additive (IV = 1 + 5 = 6)
- **Case insensitive**: Accepts both uppercase and lowercase
- **Input filtering**: Ignores invalid characters, extracts valid numerals
- **Interactive**: Continuous input until Ctrl+C

## Requirements

- Python 3.10+ (uses pattern matching syntax)
- pytest (for running tests)

## Tests

```bash
pytest -v
```

Example output:

```shell
➜  roman git:(main) ✗ pytest -v
================================================================ test session starts ================================================================
platform linux -- Python 3.12.2, pytest-8.3.4, pluggy-1.5.0 -- /home/jamey/.venv/bin/python
cachedir: .pytest_cache
rootdir: /home/jamey/Projects/turner-townsend-backend-assessment/roman
plugins: mock-3.14.0, asyncio-0.21.2
asyncio: mode=Mode.STRICT
collected 9 items

test_roman.py::test_valid_single_numerals PASSED                                                                                              [ 11%]
test_roman.py::test_valid_multiple_numerals PASSED                                                                                            [ 22%]
test_roman.py::test_lowercase_input PASSED                                                                                                    [ 33%]
test_roman.py::test_mixed_case_input PASSED                                                                                                   [ 44%]
test_roman.py::test_invalid_characters PASSED                                                                                                 [ 55%]
test_roman.py::test_mixed_valid_and_invalid_characters PASSED                                                                                 [ 66%]
test_roman.py::test_empty_string PASSED                                                                                                       [ 77%]
test_roman.py::test_only_spaces PASSED                                                                                                        [ 88%]
test_roman.py::test_spaces_and_valid_numerals PASSED                                                                                          [100%]

================================================================= 9 passed in 0.02s =================================================================
```

## Design notes

- **Simple approach**: Uses additive logic only, as the brief states complex Roman numeral rules are not required
- **User-friendly**: Filters out invalid characters rather than rejecting entire input
- **Modern Python**: Uses pattern matching (requires Python 3.10+)