Add more test coverage

[dhruvkb]

Problem

Due to the interest in adding new features, my novice status with Rust and limited time for technical debt repayment, there has been inadequate test coverage in the project. This applies to both unit tests as well as end-to-end tests.

Description

Add more tests to add confidence to the development and release workflow. This involves

• writing new unit tests for pre-existing components
• writing end-to-end tests that test individual features in isolation as well as potentially problematic combinations of features
• potential refactors that make the app easier to test