The hgvs package has many tests, including many tests for essentially the same code paths. For this issue

• Make per-gene tests optional. Instead, test by functionality.
• Fail fast. Write an early smoke test of basic functionality. Failures in this smoke test should stop testing immediately.
• Use fixtures.
• Migrate legacy unittest tests.

• Use pytest parametrize instead of manual test loops #456
• Use pytest fixtures rather than instantiating new objects #507
• Eliminate unnecessary parser invocations in tests #585