test(core): isolate fixtures from inherited scan roots

[Nanako0129]

Summary

• route pure scanner fixtures through explicit-home scanning so inherited client roots cannot change their inputs
• clear unrelated extra, headless, and same-client sibling roots from tests that intentionally exercise another environment root, while preserving dedicated positive environment coverage
• make scanner environment restoration panic-safe and run materialized parser fixtures through the existing no-environment strategy

This applies the same fixture-isolation principle as #647 to tokscale-core. Production scanning, parser behavior, cache formats, parser versions, and public APIs are unchanged.

Reproduction

With valid hostile roots supplied through HOME, XDG variables, TOKSCALE_CONFIG_DIR, TOKSCALE_EXTRA_DIRS, client-specific home variables, and TOKSCALE_HEADLESS_DIR, the pre-change default-parallel core suite reported:

test result: FAILED. 1191 passed; 27 failed; 1 ignored

A focused fixed-count fixture demonstrated the contamination directly:

test scanner::tests::test_scan_all_clients_codebuff_walks_all_three_channels_by_default ... FAILED
assertion `left == right` failed
  left: 4
 right: 3

After this change, the same hostile environment passes with the default parallel runner:

test result: ok. 1219 passed; 0 failed; 1 ignored

The remaining core integration test binaries also pass under that environment.

Verification

• cargo fmt --all -- --check
• cargo clippy --locked --workspace --all-features -- -D warnings
• cargo test --locked --workspace --all-features
• cargo build --locked --release -p tokscale-cli
• focused guard-unwind, Codebuff fixed-count, scanner-settings deduplication, and materialized Codex parser regressions
• hostile-environment cargo test -p tokscale-core with the default parallel runner
• git diff --check

Platform boundary

The local environment does not have a Windows Rust target or Windows runner, so the changed #[cfg(test)] modules were not cross-compiled or executed on Windows. The repository's Windows native checks compile release binaries only and do not compile Rust test modules; those checks therefore provide production compile coverage, not Windows test-code or runtime coverage.

---

Summary by cubic

Isolated tokscale-core test fixtures from inherited environment scan roots so env vars can’t alter test inputs. Tests now use explicit-home scanning with a panic-safe env guard; production scanning, parser behavior, caches, and public APIs are unchanged.

• Bug Fixes
  • Route pure scanner fixtures through the no-environment strategy so inherited client roots can’t add or redirect files.
  • Clear unrelated env roots in env-specific tests (e.g. TOKSCALE_EXTRA_DIRS, TOKSCALE_HEADLESS_DIR) while preserving positive environment coverage.
  • Add EnvGuard to restore env vars on unwind and shadow the parser test helper to the no-env path to keep pricing/cache behavior. Hostile env run now passes: 1219 passed, 0 failed, 1 ignored.

^{Written for commit ee97d53. Summary will update on new commits.}

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
tokscale	Ignored	Preview	Jul 17, 2026 11:36pm

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}