Tests for AI foundation layer

[anurag629]

Phase 1 — Foundation (4/4)

Comprehensive test coverage for the AI foundation layer.

Scope

tests/ai/providers.test.ts

• All 5 providers are registered with valid config
• Each provider has at least 2 models defined
• getProvider() returns correct config or undefined for unknown providers
• getModelsForProvider() returns correct model list
• getDefaultModel() returns a valid model for each provider
• Header builders produce correct auth headers per provider
• Body formatters produce the correct request shape (OpenAI vs Anthropic vs Google)

tests/ai/storage.test.ts

• setApiKey / getApiKey round-trip works for each provider
• removeApiKey clears only the specified provider
• clearAllApiKeys removes all AI-related entries, leaves other localStorage intact
• getSelectedProvider / setSelectedProvider work correctly
• getSelectedModel / setSelectedModel are per-provider
• hasAnyKeyConfigured returns true/false correctly
• Handles missing localStorage gracefully (returns null, no throw)
• Handles corrupted localStorage values gracefully

tests/api/ai-validate.test.ts

• Returns 400 for missing provider or apiKey
• Returns 400 for unknown provider
• Returns correct response shape { valid: boolean, error?: string }
• Validates request body schema

tests/api/ai-generate.test.ts

• Returns 400 for missing required fields (provider, apiKey, model, prompt)
• Returns 400 for unknown provider or model
• Returns correct response shape { content, model, usage }
• Rejects oversized prompts (if limit set)
• Validates maxTokens and temperature ranges

Mock Strategy

• Mock fetch for all provider API calls (no real API calls in tests)
• Test both success and error responses from providers
• Test provider-specific error formats (OpenAI vs Anthropic error shapes)

Acceptance Criteria

• All test files created and passing
• Provider registry fully covered
• Storage module fully covered including edge cases
• API endpoints tested for validation, success, and error paths
• No real API calls — all external requests mocked
• Coverage report shows >90% for src/lib/ai/ files