tests: fix assertions in emulator

[Kubuxu]

This PR fixes assertions checks in emulator and re-organises the
validation logic a bit to facilitate testing.

[Copilot]

Pull Request Overview

This PR fixes assertions in the emulator's test framework and reorganizes the validation logic for better testing. The changes primarily focus on improving test error messages and exposing justification validation logic for testing.

• Improves assertion error messages in the emulator for better debugging
• Refactors justification validation logic to separate concerns and enable better caching
• Fixes incorrect justification references in test cases

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
merkle/merkle_test.go	Removes t.Parallel() call to fix test execution
gpbft/validator.go	Refactors justification validation logic, moves caching logic, and extracts signature validation
gpbft/participant_test.go	Updates test names and error message expectations
gpbft/gpbft_test.go	Fixes justification references in test cases to use correct values
emulator/driver_assertions.go	Enhances assertion error messages and fixes assertion bug

Comments suppressed due to low confidence (1)

emulator/driver_assertions.go:87

• This line compares justification with itself instead of comparing it with msg.Justification. This was correctly fixed on line 88.

	d.require.True(vote.Eq(msg.Vote.Value))

[codecov]

Codecov Report

❌ Patch coverage is 86.30137% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.58%. Comparing base (993d8f7) to head (154871d).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
gpbft/validator.go	86.66%	5 Missing and 3 partials ⚠️
emulator/driver_assertions.go	84.61%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1043      +/-   ##
==========================================
- Coverage   64.91%   64.58%   -0.33%     
==========================================
  Files          80       81       +1     
  Lines        9733     9894     +161     
==========================================
+ Hits         6318     6390      +72     
- Misses       2914     2978      +64     
- Partials      501      526      +25     

Files with missing lines	Coverage Δ
emulator/driver_assertions.go	98.29% <84.61%> (-1.71%)	⬇️
gpbft/validator.go	78.81% <86.66%> (+0.17%)	⬆️

... and 9 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.