Facilitate more efficient higher-level testing

After our discussion about testing, our goal is to explore ways to make our black box tests easier to use (internally).

Potential ideas:
* Test cases: can we JUnit-parameterize common operations to make test setup easier?
* Test Granularity: for E2E tests, what assumptions make sense? Can we group those assumptions to provide easier setup? If so, perhaps we should create a smaller/unit-esque test for the variance between X setup parameters (e.g. account balances), and then in the E2E test we can make more assumptions to make setup easier
* Consider how newer team members can contribute new perspective
* ~Use external tools, e.g. smart contract tools, fuzz testing, or other, to improve testing~ this is a much bigger project at a different level of testing

No files or tests are named. Start by reviewing the existing black-box and E2E test setup, then read the linked discussion about parameterized JUnit cases, test granularity, and setup assumptions. Done should mean an agreed approach that makes common test setup easier without expanding into external tools or fuzz testing.

Written by the indexing model from the issue text.