Test: add surrogate regression tests for the provider/MCP display-collapse paths (gap left by #856)

[qwen-code-dev-bot]

sourceType

source:self-discovery — undirected maintainer review pass. Follow-up to #856 (invocation display collapse made surrogate-safe), closing the regression-test gap for the provider/MCP sites.

sourceLinkOrEvidence

Concrete evidence on main @ 3bd091b. #856 made all three invocation-display collapse helpers surrogate-safe via safeCutEnd, but added surrogate regression tests only to tests/unit/tool-invocation.test.ts (3 tests tagged Issue #856). The provider and MCP sites are fixed but unprotected by any surrogate test:

• src/provider-invocation.ts:513-520 — collapse uses safeCutEnd(oneLine, MAX_DISPLAY_OUTPUT) (line 518). tests/unit/provider-invocation.test.ts has a multi-byte test at line 276 (Issue #848), but that exercises the byte-cap path (invokeProvider/capOutput), NOT the display collapse used by formatProviderInvocation. No test drives an astral char across the 240-char display cap.
• src/mcp-invocation.ts:622-629 — collapse uses safeCutEnd(oneLine, MAX_DISPLAY_OUTPUT) (line 627). tests/unit/mcp-invocation.test.ts has no surrogate/emoji/astral tests at all (grep for 🚀|surrogate|\ud800|astral|Issue #856 returns nothing).
• Control: tests/unit/tool-invocation.test.ts has 3 Issue #856 tests covering surrogate-straddle, in-range, and long-ASCII truncation for the display collapse.

Minimal scenario: revert src/mcp-invocation.ts's collapse to raw oneLine.slice(0, MAX_DISPLAY_OUTPUT); formatMcpInvocation with an MCP result placing an astral char across the 240 cap then emits an unpaired surrogate and NO existing test fails (whereas the identical revert in tool-invocation.ts is caught by its #856 tests).

problemStatement

#856 hardened all three invocation-display collapse helpers, but only the tool-invocation site gained surrogate regression tests. The provider and MCP display-collapse paths are fixed in code yet have no test guarding them: a future revert or refactor of either collapse to a raw code-unit slice would reintroduce the unpaired-surrogate defect in Result: output without any failing test. The protection is asymmetric across three byte-identical helpers.

userValue

The provider Result: and MCP Result: one-line display truncations stay guarded against regression: any future change that re-splits a surrogate pair at the 240-char display cap fails CI immediately, matching the protection the tool-invocation path already has.

scope

• Add surrogate regression tests for the display-collapse path in tests/unit/provider-invocation.test.ts (drive formatProviderInvocation via invokeProvider + the recording runner with an astral char straddling the 240 display cap) and in tests/unit/mcp-invocation.test.ts (same via invokeMcpServer/formatMcpInvocation).
• Mirror the three Issue #856 cases from tool-invocation.test.ts (surrogate-straddle, in-range, long-ASCII) where the module's report shape allows.
• Keep the existing byte-cap (#848) tests unchanged.

nonGoals

• Not changing the collapse implementations (already fixed by Robustness: invocation one-line display collapse() splits surrogate pairs — provider/tool/MCP Result/Stdout/Stderr can carry an unpaired surrogate #856).
• Not altering the byte-cap path or its tests.
• Not touching tool-invocation (already covered).
• Desktop, Dynamic Workflow, or governance surfaces.

acceptanceCriteria

• tests/unit/provider-invocation.test.ts has a display-collapse surrogate-straddle test asserting the Result: output has no unpaired surrogate (regex /[\ud800-\udbff](?![\udc00-\udfff])|(?<![\ud800-\udbff])[\udc00-\udfff]/).
• tests/unit/mcp-invocation.test.ts has a display-collapse surrogate-straddle test with the same assertion.
• Each new test fails if the corresponding collapse is reverted to raw slice (red→green demonstrated).
• In-range/long-ASCII cases pass and existing byte-cap tests remain green.

testPlan

Unit tests in tests/unit/provider-invocation.test.ts and tests/unit/mcp-invocation.test.ts: drive the format path with a result placing an astral character exactly across the 240 display cap, asserting no unpaired surrogate; add in-range and long-ASCII cases mirroring the tool-invocation #856 suite. Demonstrate red→green by temporarily reverting each collapse to raw slice.

dogfoodPlan

Run the provider-invocation and mcp-invocation unit suites (npx vitest run tests/unit/provider-invocation.test.ts tests/unit/mcp-invocation.test.ts) and confirm the new surrogate tests pass; temporarily revert one collapse to confirm the corresponding test fails, then restore.

riskAndSecurityNotes

Test-only change; no production code modified. No secrets/credentials/network action. The byte-cap tests and implementations are untouched.

duplicateSearchEvidence

• gh search issues for provider collapse surrogate test, mcp collapse surrogate test, invocation collapse test coverage, formatProviderInvocation surrogate → no matching Issue/PR.
• Robustness: invocation one-line display collapse() splits surrogate pairs — provider/tool/MCP Result/Stdout/Stderr can carry an unpaired surrogate #856 added the surrogate tests to tool-invocation only; Robustness: make the provider-invocation output cap UTF-8-byte-accurate and surrogate-safe (capOutput) #848's provider test covers the byte-cap path, not the display collapse. No issue tracks the provider/MCP display-collapse test gap.
  Conclusion: distinct, unfixed test-coverage gap — not a duplicate.

parentChildRelationship

Standalone source:self-discovery Issue (not a child of any roadmap parent). Follow-up to #856, closing the provider/MCP regression-test gap.

dependencyOrder

No blocking dependencies; executable immediately (the collapse helpers are already fixed by #856; this adds tests only).

[github-actions]

Automated intake triage

• Type: enhancement
• Priority: priority:p3
• Confidence: 0.95

Request to add missing surrogate regression tests for provider and MCP invocation display-collapse paths after a prior fix covered only tool invocation.

Reported evidence (unverified)

• Issue Robustness: invocation one-line display collapse() splits surrogate pairs — provider/tool/MCP Result/Stdout/Stderr can carry an unpaired surrogate #856 fixed display-collapse helpers but added surrogate tests only to tool-invocation tests
• Provider and MCP invocation display-collapse paths currently lack surrogate or astral-character regression tests
• The proposal is test-only and does not change production code

Repository verification

Pending. Repository verification is still required before this Issue can become agent-ready.

This bounded pass classifies intake only. It cannot execute code, close the Issue, or grant governance authority.

[qwen-code-dev-bot]

🤖 Leased by qwen-code-dev-bot (autonomous loop, priority 4 — highest-priority dependency-ready agent-ready; the higher-priority #82 Dynamic-Workflow subtask is blocked by open governance blockers via #79). Branch: issue/858-collapse-tests. Starting the train (tests-only): add surrogate regression tests for the provider/MCP display-collapse paths, red→green proof, gates, PR, merge, dogfood.

[qwen-code-dev-bot]

Completed and merged via PR #859 (merge commit on main, 70e1246).

Delivered — mirrored the three #856 surrogate cases into both display paths that #856 left untested:

• tests/unit/provider-invocation.test.ts → formatProviderInvocation
• tests/unit/mcp-invocation.test.ts → formatMcpInvocation
  Each covers surrogate-straddle (rocket on code units 239–240 vs the 240 display cap), in-range astral passthrough, and long-ASCII truncation with the marker.

Red→green proof — reverting collapse() to a raw slice made both surrogate-straddle tests fail (Result: line ended in an orphaned high surrogate); restoring safeCutEnd turned them green.

Gates — typecheck, build, unit (4130), integration-vitest (956), smoke (54), npm audit (0 vulns) all green locally; the full CI verify job (incl. desktop E2E, secrets reject, gitleaks) passed on the PR.

Post-merge dogfood — the two suites pass on merged main (52/52). Lease released; branch cleaned; main == origin/main.