test: comprehensive test coverage improvements (pure functions, SDK validation, command tests)

[NianJiuZst]

Summary

Adds comprehensive test coverage across four categories: pure utilities, SDK validation logic, thin command tests, and polling logic.

277 → 285 tests (+70 new, some existing tests enhanced)

Changes by category

Pure function unit tests (5 commits)

Commit	Module	Tests	Coverage
maskToken	utils/token.ts	5	short/long/empty/edge cases
CLIError/SDKError	errors/base.ts	7	constructors, toJSON(), hint
isInteractive/isCI	utils/env.ts	10	TTY detection, CI env vars
parseConfigFile	config/schema.ts	17	api_key, region, output, timeout, proxy, OAuth, default models, unknown keys

SDK validateParams tests (5 commits)

All SDK validation rules now tested — previously 0% coverage:

Module	Tests	Coverage
SpeechSDK	2	text required (missing + empty)
ImageSDK	6	width/height paired, range, multiple-of-8, valid passes
VideoSDK	6	prompt, SEF/S2V mode constraints, Fast model, auto-selection
MusicSDK	8	instrumental+lyrics, lyrics_optimizer conflicts, missing fields, model/format validation, stream+url conflict
TextSDK	2	empty messages, defaults applied

Command test improvements (4 commits)

Command	Before	After	Added
image generate	2 tests	9 tests	width/height validation, out constraint, dry-run body
file upload	2 tests	4 tests	file existence, dry-run with purpose
search query	2 tests	4 tests	mock server: results display, empty results
quota show	2 tests	2 tests	improved structure

Polling logic (1 commit)

Module	Tests	Coverage
polling/poll.ts	4	complete, failed with message, timeout, immediate success

Test results

285 tests / 0 fail / typecheck: clean

Design notes

• SDK validation tests call methods without mock servers — validation happens before any network call, so missing/invalid params throw immediately
• quota show mock server test was not possible because quotaEndpoint() rewrites the hostname to api.* subdomain, which breaks localhost mock server routing
• 14 "Unhandled error between tests" warnings are pre-existing — present on origin/main before any of these changes

Files changed

File	Status	Tests
test/utils/token.test.ts	New	5
test/errors/base.test.ts	New	7
test/utils/env.test.ts	New	10
test/config/schema.test.ts	New	17
test/polling/poll.test.ts	New	4
test/sdk/text.test.ts	Modified	+2
test/sdk/image.test.ts	Modified	+6
test/sdk/video.test.ts	Modified	+6
test/sdk/music.test.ts	Modified	+8
test/sdk/speech.test.ts	Modified	+2
test/commands/image/generate.test.ts	Modified	+7
test/commands/file/upload.test.ts	Modified	+2
test/commands/search/query.test.ts	Modified	+2
test/commands/quota/show.test.ts	Modified	improved