Add code coverage

[colemancda]

Adds code coverage measurement, reporting, and CI enforcement — and, along the way, raises coverage from a 70.68% baseline to 88.35%, fixes several source bugs the new tests uncovered, and makes the unit tests actually run on more platforms in CI.

Coverage tooling

• Scripts/coverage.sh runs the suite with coverage, exports LCOV (coverage.lcov) and Cobertura (coverage.xml) reports scoped to this package's own sources under Sources/ (dependencies and tests excluded), and fails if line coverage drops below the threshold.
• New Code Coverage GitHub Actions job runs the script on macOS, uploads the Cobertura report to GitHub Code Quality for per-PR display, and archives both reports.
• Threshold is ratcheted up as coverage grows; currently 87% (measured 88.35%).
• COVERAGE_PLAN.md documents the phased path toward 95%.

New tests (70.68% → 88.35%)

• HCI: round-trip encode/decode/reject tests for ~110 previously-untested command/event types (classic, LE connection, LE advertising, LE privacy/test-mode).
• GATT/ATT: untested ATT PDUs, GATT service/characteristic types, the GATTDatabase value-type API, and end-to-end GATTClient ⇄ GATTServer procedures (reads, long reads, read-by-type, short/long/no-response writes, error responses) over the in-memory L2CAP transport.
• GAP: service-solicitation UUID lists, Security Manager OOB/TK, Simple Pairing hash/randomizer.

Source bug fixes (found by the new tests)

• HCIReadLMPHandleReturn validated against the wrong length and misordered its fields — could never decode through the HCI transport.
• HCILEGenerateDHKey encoded 65 bytes instead of 64 (duplicated two bytes, dropped one).
• HCILEReadLocalResolvableAddressReturn / HCILEReadPeerResolvableAddressReturn read 8 bytes from a 6-byte payload — trapped out-of-bounds on any valid response.
• HCILETransmitterTest omitted the Length_Of_Test_Data byte.
• GATTDatabase.add(service:) never recorded included-service handles, tripping an assertion (a debug-build trap) for any service with included services.

Deduplication

• The shared Hexadecimal, Integer, System, String, and Bool extensions were copied internal into every target. Consolidated one package-access copy each into the core Bluetooth target and removed 12 duplicate files (~1,200 lines).

CI: run the unit tests on more platforms

• Windows: now runs swift test (previously build-only).
• Android: the full suite now runs on the x86_64 emulator (the only Android ABI GitHub-hosted runners can hardware-accelerate), and the tests are cross-compiled for aarch64 and armv7 as a compile-verification step. This mirrors the official Swift Android SDK CI — hosted runners have no KVM for ARM emulators and armv7 emulator images are unavailable, so arm ABIs are build-verified rather than executed.

Note: the new Android/Windows CI jobs and the coverage-upload step could not be exercised locally; the local suite (macOS) is green at 88.35%.

[github-code-quality]

Code Coverage Overview

Languages: Swift

Swift / code-coverage/llvm-cov

The overall coverage in the feature/code-coverag... branch is 88%. Coverage data for the master branch is not yet available.

Show a code coverage summary of the most covered files.

File	master	feature/code-coverag... e6cd0d1	+/-
Sources/Bluetoo...asurement.swift	—	100%	—
Sources/Bluetoo...h/UInt128.swift	—	96%	—
Sources/Bluetoo...ainerData.swift	—	95%	—
Sources/Bluetoo...toothUUID.swift	—	95%	—
Sources/Bluetoo...TDatabase.swift	—	92%	—
Sources/Bluetoo...isingData.swift	—	92%	—
Sources/Bluetoo.../ATTError.swift	—	88%	—
Sources/Bluetoo...ATTClient.swift	—	85%	—
Sources/Bluetoo...onnection.swift	—	81%	—
Sources/Bluetoo...ATTServer.swift	—	79%	—

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_{Updated July 18, 2026 05:16 UTC
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