[Apr20] Technical Debt Week

[mratsim]

In preparation for audit we need to pay our technical debt.

Goals:

• After audit it will be significantly harder to change the codebase if we don't want to invalidate the audit.
• The codebase has accumulated cruft, in particular when pushing for the tesnet in March 2019 and the interop event in September 2019. Cleaning this up will help documentation which will help auditors getting up to speed with our codebase.
• Part of the codebase has poor test coverage. In the future we will likely require significant refactoring, with a well covered test suite, those refactorings will be much less likely to introduce regressions and those will be easier to narrow down too.

This is a meta-issue, please create linked issues in the relevant codebase with desired concrete and actionable outcomes.
In particular "improve network stability" is not enough.

Identified targets:

1. Simplification of the codebase to ease debuggability:

• Usage and/or debugging of macros in network protocols

2. Improve test coverage of:

• block pool
• validator pool
• attestation pool

[mratsim]

• Separate validator duties from the Beacon Node #976 - Separate validator duties from BeaconNode
• Attest immediately if block from proposer - fix #966 #1014 - [Postponed] Attest immediately if block from expected proposer
• Revive nbench #1022 - Revive nbench and add it to test suite
• Split blockpool responsibilities #1028 - [Postponed] Split blockpool repsonsibilities
• Split quarantine #1038 - Splitoff quarantine

[mratsim]

Additionally all the result/error and Exceptions refactorings