Write a ton of tests

[Panadero1]

What MVP does your issue request work on?

• Physics based dice roller
• GM customization options to all input
• Create Exploration or Encounter modes
• Add players/NPCS/Beasts/Shops
• Integrated search engine
• Notes Feature
• Documentation & Automation Tools
• Testing

Describe the solution you'd like
Writing tests according to the testing approach plan to get good initial coverage and catch bugs

Describe alternatives you've considered
N/A

Additional context
See #91's implementation

[Panadero1]

Adding tests will cover the next week as well