Fix remote configs hash caching, custom fields validation; add event tests

[Gogoshika-ga]

Fixes

• configs_hash cleared on every launch: ensurePersistedStates erased the cached hash whenever last_used_identifier existed, instead of only when the identifier changed (matching the iOS/C# SDKs). As a result the init request always sent an empty configs_hash and the backend re-sent full configs every session.
• Thread safety: remote configs listeners and _gameRemoteConfigsJson were written without the mutex that readers hold; listeners are now notified from a snapshot outside the lock.
• Custom fields: a non-string value under an illegal key threw while logging the rejection, silently discarding the entire custom fields payload.
• Coverage job: gcov counters are now updated atomically (-fprofile-update=atomic); the SDK's worker thread produced torn counters that newer lcov rejects.

Tests

• Regression tests for configs_hash persistence (kept on same identifier, cleared on change) — verified to fail against the old code.
• Ported the old commented-out custom fields validation test to nlohmann, asserting current behavior (booleans are now accepted) against the MAX_CUSTOM_FIELDS_* limits, plus a regression test for the discarded-payload bug.
• New GAEventsTests.cpp: event store and send queue tests using a mock HTTP client — storing/annotating all event types, transaction/attempt counters, and the flush path (batch send, retry on no response, drop on server error).
• Event submission is disabled suite-wide in test/main.cpp (re-enabled per-fixture against the mock), so tests can never send events to the GA servers.

Local coverage: 34.8% → 54.9% lines (GAEvents.cpp 7.6% → 54.6%).

Code coverage (new setup)

Replaces the removed lcov/genhtml setup with gcovr:

• Local: python3 setup.py --platform <p> --build --test --coverage builds instrumented, runs the tests, and opens an HTML report (build/coverage/index.html). Requires gcovr (e.g. brew install gcovr).
• Shared config: filters and exclusions (SDK sources only, Platform/ and vendored deps excluded, throw-branches excluded) live in gcovr.cfg, used identically by local runs and CI.
• CI (coverage.yml): single ubuntu-24.04/gcc job on PRs to main, pushes to main, and manual dispatch. Gates: line ≥ 60, branch ≥ 50, function ≥ 80 (~5pts under the measured gcc baseline of 63.4/55.5/84.6). Emits the summary to the job log/summary, uploads the detailed HTML as an artifact (also when the gate fails), uploads to Codecov via tokenless OIDC, and publishes the report to GitHub Pages on pushes to main. Report steps are skipped when the build itself fails.
• README: Codecov badge + --coverage docs.

[github-actions]

LCOV of commit 954f28d during Test Coverage #170

📊 Summary Coverage

Metric	Coverage	Details
📈 Lines	🔴 69.5%	2309 / 3323 lines
🔧 Functions	🟡 84.3%	418 / 496 functions
🌿 Branches	🔴 40.7%	2286 / 5613 branches

📁 Files Changed Coverage

File	Lines	Functions	Branches
include/GameAnalytics/GAHttpClient.h	🔴 0.0% (4)	🔴 0.0% (3)	🔴 0.0% (2)
source/gameanalytics/GAState.cpp	🟡 85.6% (599)	🟢 94.0% (84)	🔴 46.9% (1323)
source/gameanalytics/GAState.h	🟢 91.2% (34)	🟡 88.9% (9)	🔴 60.0% (50)

🟢 ≥ 90% · 🟡 ≥ 70% · 🔴 below 70% · ⚪ no data
Full coverage report

[codecov-commenter]

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[Copilot]

Pull request overview

This PR updates the C++ SDK’s remote-config caching and listener handling to match expected cross-session behavior, hardens custom-fields validation, and introduces broader regression/integration tests alongside a new gcovr-based coverage workflow.

Changes:

• Fix configs_hash persistence across launches (only clear when the user identifier changes) and adjust remote-config listener notifications for safer concurrency.
• Fix a custom-fields validation/logging edge case where an invalid entry could discard the entire payload.
• Add new GAState / GAEvents / public-facade integration tests and replace coverage reporting with gcovr + CI gating/upload.

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
test/main.cpp	Disables event submission by default for the whole test suite.
test/helpers/GAStateTestAccessor.h	Adds a test-only accessor to drive GAState transitions deterministically.
test/GAStateTests.cpp	Adds regression tests for configs hash persistence and custom-fields validation behavior.
test/GameAnalyticsApiTests.cpp	Adds integration tests for the public GameAnalytics facade using a mock HTTP client.
test/GAEventsTests.cpp	Adds unit tests for event storage/flush behavior and retry/drop semantics.
source/gameanalytics/GAState.h	Exposes GAState internals to tests via a new friend declaration.
source/gameanalytics/GAState.cpp	Fixes configs-hash clearing logic; adds locking/snapshotting for remote-config listeners; hardens custom-fields logging.
source/gameanalytics/GACommon.h	Bumps SDK version string to cpp 5.4.1.
setup.py	Adds gcovr coverage report generation and a CI-friendly --no_cov_report flag.
README.md	Adds Codecov badge and updates --coverage documentation.
gcovr.cfg	Defines shared gcovr filters/exclusions for local and CI coverage runs.
CMakeLists.txt	Replaces lcov targets with compiler/linker coverage instrumentation flags.
CHANGELOG.md	Documents fixes included in 5.4.1.
.gitignore	Ignores Python bytecode (*.pyc).
.github/workflows/coverage.yml	Adds a dedicated gcc/ubuntu coverage job with gating, artifacts, Codecov upload, and Pages publishing on main.
.github/workflows/cmake.yml	Adds vcpkg binary caching to speed up CI builds.

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