WIP test(fxa-auth-server): migrate 16 OAuth Mocha test files to Jest PART 5

[vbudhram]

Because

• The auth-server OAuth tests used Mocha/Chai/Proxyquire while the rest of the test suite is migrating to Jest
• Mixed test frameworks increase maintenance burden and prevent unified test infrastructure (shared global setup/teardown, consistent mocking patterns)
• Jest co-located .spec.ts files improve discoverability and align with project conventions

This pull request

• Migrates all 16 OAuth test files from test/oauth/ to Jest with full test parity (337 tests preserved)
• Adds 13 co-located unit test .spec.ts files next to source in lib/
• Adds 5 integration test .in.spec.ts files in test/remote/
• Splits 2 mixed files (grant.js, routes/token.js) into separate unit and integration test files
• Adds '^fxa-shared$' moduleNameMapper to jest.integration.config.js to prevent ScopeSet class identity mismatch
• Adds CORS_ORIGIN env var to jest-setup-env.ts and jest-global-setup.ts for test parity with CI
• Mocks ESM-only packages (@octokit/rest, p-queue) in oauth_api.in.spec.ts via jest.mock()

Issue

Closes: https://mozilla-hub.atlassian.net/browse/FXA-12565

Checklist

• My commit is GPG signed
• Tests pass locally (if applicable)
• Documentation updated (if applicable)
• RTL rendering verified (if UI changed)

Other Information

Test Parity

337 old → 337 new (336 active + 1 skipped)

Unit Tests (co-located .spec.ts)

Old File	New File	Tests	Status
test/oauth/util.js	lib/oauth/util.spec.ts	1	Exact
test/oauth/token.js	lib/oauth/token.spec.ts	1	Exact
test/oauth/assertion.js	lib/oauth/assertion.spec.ts	11	Exact
test/oauth/jwt.js	lib/oauth/jwt.spec.ts	11	Exact
test/oauth/jwt_access_token.js	lib/oauth/jwt_access_token.spec.ts	11	Exact
test/oauth/jwt_id_token.js	lib/oauth/jwt_id_token.spec.ts	12	Exact
test/oauth/jwt_sub.js	lib/oauth/jwt_sub.spec.ts	10	Exact
test/oauth/keys.js	lib/oauth/keys.spec.ts	15	Exact
test/oauth/routes/authorization.js	lib/routes/oauth/authorization.spec.ts	16	Exact
test/oauth/routes/jwks.js	lib/routes/oauth/jwks.spec.ts	1	Exact
test/oauth/routes/verify.js	lib/routes/oauth/verify.spec.ts	6	Exact

Split Files (unit + integration)

Old File	Unit	Integration	Tests	Status
test/oauth/grant.js	lib/oauth/grant.spec.ts	test/remote/oauth_grant.in.spec.ts	13+3=16	Exact
test/oauth/routes/token.js	lib/routes/oauth/token.spec.ts	test/remote/oauth_token_route.in.spec.ts	29+4=33	Exact

Integration Tests (test/remote/*.in.spec.ts)

Old File	New File	Tests	Status
test/oauth/api.js	test/remote/oauth_api.in.spec.ts	163	1 skip*
test/oauth/db/index.js	test/remote/oauth_db.in.spec.ts	29	Exact
test/oauth/key-management-scripts.js	test/remote/oauth_key_management.in.spec.ts	1	Exact

How to test

cd packages/fxa-auth-server

# Unit tests (13 files, 138 tests)
npx jest --no-coverage --forceExit lib/oauth/*.spec.ts lib/routes/oauth/*.spec.ts

# Integration tests (5 files, 200 tests — requires infrastructure)
yarn start infrastructure  # in separate terminal
npx jest --config jest.integration.config.js --forceExit test/remote/oauth_*.in.spec.ts