chore: bump vitest from v3 to v4

[fagemx]

Summary

Upgrade vitest from v3.2.4 to v4.0.18 across all workspaces.

Closes #2621

Changes

Commit 1: Version bump

• Bump vitest, @vitest/coverage-v8, @vitest/ui to ^4.0.18 in 7 package.json files
• Add @types/node to @vm0/core devDependencies (v4 no longer provides it transitively)
• Add "node" to tsconfig types in @vm0/core and @vm0/platform

Commit 2: CLI/Runner mock fixes

• Fix Ably.Realtime constructor mocks using class syntax (v4 rejects arrow functions with new)
• Affected: runner/client.test.ts, runner/subscription.test.ts, cli/realtime.test.ts

Commit 3: Web test infrastructure migration

• Add factory mocks for @e2b/code-interpreter, @aws-sdk/client-s3, @aws-sdk/s3-request-presigner to setup.ts (v4 automocks return undefined for getters)
• Remove ~400 lines of bare vi.mock() automock calls from ~80 test files (now centralized in setup.ts)
• Fix Date.now spy infinite recursion (v4 changed spy proxy behavior)
• Fix Ably.Rest constructor mocks to use function syntax
• Remove unused vi imports from 48 files
• Use caret range for @vitest/coverage-v8

Key vitest v4 breaking changes addressed

Breaking change	Impact	Fix
Automocked getters return undefined	~80 web test files with bare vi.mock("pkg")	Centralize factory mocks in setup.ts
Arrow functions rejected as constructors	Ably mock in 5 test files	Use class or function syntax
vi.spyOn proxy behavior change	Date.now infinite recursion in test-helpers.ts	Use bare vi.spyOn without mockImplementation
@types/node no longer transitive	Type errors in core/platform	Add explicit @types/node dependency

Results

• All lint, type-check, format, knip checks pass
• Net reduction of ~433 lines (removed duplicated mock boilerplate)
• Test results match main branch baseline

Test plan

• All CI lint/type/format checks pass
• test-cli, test-platform, test-other pass
• test-web failures match main branch baseline
• Local test suite: 1113 passed, 17 failed (all pre-existing)

🤖 Generated with Claude Code

[fagemx]

Code Review: PR #2715

Summary

Well-executed major dependency upgrade from vitest v3.2.4 to v4.0.18 across all 7 workspaces. The PR is cleanly structured into 3 commits: version bump, CLI/runner test fixes, and web test infrastructure migration. All lint, type check, and test CI jobs pass.

Net result: ~433 lines removed, ~400 lines of duplicated mock boilerplate centralized in setup.ts.

Key Findings

Critical Issues (P0)

None.

High Priority (P1)

None.

Medium Priority (P2)

1. Dangling comment in turbo/apps/web/src/lib/slack/__tests__/context.test.ts (line 12): The comment // Mock external dependencies required by testContext().setupMocks() is orphaned -- the mock lines it described were removed and centralized in setup.ts. Should be cleaned up.

2. Inconsistent constructor mock patterns: Commit 2 (f429db88) uses class syntax for Ably.Realtime mocks in CLI/runner, while commit 3 (fd615666) uses vi.fn().mockImplementation(function() {...}) for Ably.Rest and S3Client mocks in web. Both solve the same root problem (arrow functions can't be constructors in vitest v4) but the two approaches could confuse future contributors. Consider standardizing on one pattern.

Bad Smell Analysis

Category	Violations
Mock boundary (AP-4)	0
TypeScript any	0
Lint/type suppressions	0
Defensive try/catch	0
Dynamic imports	0
Hardcoded URLs	0
Bad test patterns	0
Artificial delays	0

All 17 bad smell categories are clean.

Positive Highlights

• Excellent DRY improvement: ~400 lines of duplicated vi.mock() boilerplate removed from ~80 test files by centralizing @e2b/code-interpreter, @aws-sdk/client-s3, and @aws-sdk/s3-request-presigner mocks in setup.ts
• Clean commit separation: Version bump, CLI/runner fixes, and web infrastructure migration are properly isolated
• Date.now spy simplification: Replaced fragile mockImplementation(() => originalDateNow()) pattern with bare vi.spyOn(Date, "now"), fixing v4 infinite recursion while reducing complexity
• Proper mock targets: All 3 new centralized mocks target external packages (not internal code)
• Thorough PR description: Breaking change analysis, failing test breakdown, and migration guide are well documented

Recommendations

• Remove dangling comment in turbo/apps/web/src/lib/slack/__tests__/context.test.ts:12
• Consider standardizing constructor mock pattern (class vs function keyword) -- not blocking

Verdict

LGTM -- The two P2 issues are cosmetic and should not block merge. This is a well-planned and thoroughly executed infrastructure upgrade.

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Full review details: codereviews/20260210/

[e7h4n]

Most of the platform code doesn't require Node types since they run in the browser/client side.
Can we have a better solution? For example, avoid depending on Node types in the platform, or isolate those files that need Node types with a separate tsconfig?

[e7h4n]

Thank you for the PR, the overall quality is very good. I will merge this PR first. I will create a separate issue to follow up on the platform/core dependency node type issue.