test(core): fix the NetMonitorCore runner crash and DST-dependent expiry test (#330)

[jbcrane13]

Problem

The full swift test in NetMonitorCore failed on main in two ways (reproduced on mini-pro-2 at 5f002e3):

1. Runner crash (signal 5). The crash report (swiftpm-testing-helper-2026-09-28-233146.ips) traps inside Foundation's URLSession.data(for:) completion. Nine suites share MockURLProtocol's global requestHandler. Each is .serialized, but separate serialized suites still run in parallel, and every test's init() sets the handler to nil. A test in one suite cleared the handler another suite's request was using; the mock then finished the load with no response, and data(for:) trapped. Only 926 of about 1,464 tests had finished when the runner died.
2. "Expiry calculation: days between two known dates" counted 59 days, not 60: 60 × 86400 s from Date() crosses the 1 Nov DST change in the local zone.

Fix (tests only; no app code changes)

• GlobalMockURLProtocolSuites is a serialized parent suite, and the nine global-handler suites are nested under it in extensions, so they run one at a time. .serialized covers nested suites.
• With no handler, MockURLProtocol now fails the request with URLError(.resourceUnavailable) instead of finishing without a response, so a future race fails one test rather than ending the run.
• The two expiry-calculation tests use a fixed date (2026-10-15 UTC) and a UTC Gregorian calendar.

The six suite files are reindented only; review with git diff -w (48+/9−).

Verification (mini-pro-2, under lockf /tmp/nm-node-test.lock)

• Before (main 5f002e3): 1 failure + exited with unexpected signal code 5
• After (d32e2e9), two consecutive full runs: ✔ Test run with 1464 tests in 187 suites passed both times

Not part of 2.2.1 build 16. Only tests change, so no new build is needed.

Closes #330

🤖 Generated with Claude Code

https://claude.ai/code/session_012SGbgc2WtUFjD4SKcoa2bt

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[Copilot]

Copilot review overview

🔵 Needs a closer look

The change is a large, CI-critical reindentation of shared test infrastructure whose runtime correctness depends on Swift Testing serialization behavior that cannot be executed in this review environment, so a human should confirm before approval.

Review effort: Balanced
Findings: None

What changed in this PR

This test-only PR fixes two pre-existing failures in the NetMonitorCore package's full swift test run (issue #330): a signal 5 runner crash and a DST-sensitive SSL-expiry test. No application code changes.

The runner crash was caused by nine .serialized suites that share MockURLProtocol's global requestHandler: separate serialized suites still run in parallel, and each test's init() reset the handler while another suite's request was mid-flight, leaving a request with no handler that finished without a response and trapped inside URLSession.data(for:). The fix serializes all nine suites under a single @Suite(.serialized) parent and hardens the no-handler path.

Changes:

• Introduce a @Suite(.serialized) enum GlobalMockURLProtocolSuites and nest all nine global-handler suites under it (via extensions) so they run one at a time.
• Make MockURLProtocol fail a handler-less request with URLError(.resourceUnavailable) instead of finishing empty (which trapped the run).
• Make the two expiry-calculation tests deterministic using a fixed 2026-10-15 00:00 UTC date and a UTC Gregorian calendar.

File	Description
Helpers/​MockURLProtocol.swift	Adds the GlobalMockURLProtocolSuites serialized parent; fails handler-less requests instead of trapping; updates doc comments.
ContractTests.swift	Nests the suite (and its inner contract sub-suites) under GlobalMockURLProtocolSuites; reindent only.
GeoLocationServiceTests.swift	Nests the suite under GlobalMockURLProtocolSuites; reindent only.
WorldPingServiceErrorTests.swift	Nests the suite under GlobalMockURLProtocolSuites; reindent only.
WorldPingRegressionTests.swift	Nests both suites under GlobalMockURLProtocolSuites; reindent only.
SpeedTestServiceSessionTests.swift	Nests three suites under GlobalMockURLProtocolSuites; reindent only.
SpeedTestServiceErrorRecoveryTests.swift	Nests the suite under GlobalMockURLProtocolSuites; reindent only.
SSLCertificateContractTests.swift	Replaces Date()/Calendar.current with a fixed UTC date and calendar in the two expiry tests.

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