Description

The current HttpClient implementation and its tests relied on real external HTTP APIs, which made the test suite slow, flaky, and environment-dependent.
This change aims to make HttpClient unit-testable in isolation while preserving full backward compatibility and existing behavior.

Requirements

HttpClient changes

• HttpClient MUST allow injecting a Curl instance into createRequest()
• HttpClient MUST allow injecting a MultiCurl instance into:
  • createMultiRequest()
  • createAsyncMultiRequest()
• If no client is injected, HttpClient MUST continue to instantiate Curl / MultiCurl internally (BC preserved)
• No external HTTP requests should be required to exercise HttpClient logic in tests
• Public API behavior MUST remain unchanged for existing consumers

Test suite changes

• All HttpClient unit tests MUST be rewritten to:
  • avoid external APIs
  • avoid real network calls
  • use mocks for Curl and MultiCurl
• Tests MUST cover:
  • single request flow
  • multi request response normalization (headers, cookies, body)
  • async multi request callback registration
  • error handling for single and multi requests
  • request header interception and case-insensitivity
  • passthrough helpers (info(), url())
• Tests MUST be deterministic and runnable offline
• External API–specific assertions MUST be removed