A test fails in `checkout()`, and the assertion concerns jurisdiction rounding. Which exp…

A test fails in `checkout()`, and the assertion concerns jurisdiction rounding. Which expansion is best?

1. Trace from the test to `checkout()`, its tax dependency, jurisdiction configuration, and relevant callers and tests
2. Load every file whose name contains `checkout` and stop there
3. Read only the assertion because it already describes the expected value
4. Load the largest source files first because they contain more context