1  """Regression tests for Copilot api_mode recomputation during /model switch.
  2  
  3  When switching models within the Copilot provider (e.g. GPT-5 → Claude),
  4  the stale api_mode from resolve_runtime_provider must be overridden with
  5  a fresh value computed from the *new* model.  Without the fix, Claude
  6  requests went through the Responses API and failed with
  7  ``unsupported_api_for_model``.
  8  """
  9  
 10  from unittest.mock import patch
 11  
 12  from hermes_cli.model_switch import switch_model
 13  
 14  
 15  _MOCK_VALIDATION = {
 16      "accepted": True,
 17      "persist": True,
 18      "recognized": True,
 19      "message": None,
 20  }
 21  
 22  
 23  def _run_copilot_switch(
 24      raw_input: str,
 25      current_provider: str = "copilot",
 26      current_model: str = "gpt-5.4",
 27      explicit_provider: str = "",
 28      runtime_api_mode: str = "codex_responses",
 29  ):
 30      """Run switch_model with Copilot mocks and return the result."""
 31      with (
 32          patch("hermes_cli.model_switch.resolve_alias", return_value=None),
 33          patch("hermes_cli.model_switch.list_provider_models", return_value=[]),
 34          patch(
 35              "hermes_cli.runtime_provider.resolve_runtime_provider",
 36              return_value={
 37                  "api_key": "ghu_test_token",
 38                  "base_url": "https://api.githubcopilot.com",
 39                  "api_mode": runtime_api_mode,
 40              },
 41          ),
 42          patch(
 43              "hermes_cli.models.validate_requested_model",
 44              return_value=_MOCK_VALIDATION,
 45          ),
 46          patch("hermes_cli.model_switch.get_model_info", return_value=None),
 47          patch("hermes_cli.model_switch.get_model_capabilities", return_value=None),
 48          patch("hermes_cli.models.detect_provider_for_model", return_value=None),
 49      ):
 50          return switch_model(
 51              raw_input=raw_input,
 52              current_provider=current_provider,
 53              current_model=current_model,
 54              explicit_provider=explicit_provider,
 55          )
 56  
 57  
 58  def test_same_provider_copilot_switch_recomputes_api_mode():
 59      """GPT-5 → Claude on copilot: api_mode must flip to chat_completions."""
 60      result = _run_copilot_switch(
 61          raw_input="claude-opus-4.6",
 62          current_provider="copilot",
 63          current_model="gpt-5.4",
 64      )
 65  
 66      assert result.success, f"switch_model failed: {result.error_message}"
 67      assert result.new_model == "claude-opus-4.6"
 68      assert result.target_provider == "copilot"
 69      assert result.api_mode == "chat_completions"
 70  
 71  
 72  def test_explicit_copilot_switch_uses_selected_model_api_mode():
 73      """Cross-provider switch to copilot: api_mode from new model, not stale runtime."""
 74      result = _run_copilot_switch(
 75          raw_input="claude-opus-4.6",
 76          current_provider="openrouter",
 77          current_model="anthropic/claude-sonnet-4.6",
 78          explicit_provider="copilot",
 79      )
 80  
 81      assert result.success, f"switch_model failed: {result.error_message}"
 82      assert result.new_model == "claude-opus-4.6"
 83      assert result.target_provider == "github-copilot"
 84      assert result.api_mode == "chat_completions"
 85  
 86  
 87  def test_copilot_gpt5_keeps_codex_responses():
 88      """GPT-5 → GPT-5 on copilot: api_mode must stay codex_responses."""
 89      result = _run_copilot_switch(
 90          raw_input="gpt-5.4-mini",
 91          current_provider="copilot",
 92          current_model="gpt-5.4",
 93          runtime_api_mode="codex_responses",
 94      )
 95  
 96      assert result.success, f"switch_model failed: {result.error_message}"
 97      assert result.new_model == "gpt-5.4-mini"
 98      assert result.target_provider == "copilot"
 99      # gpt-5.4-mini is a GPT-5 variant — should use codex_responses
100      # (gpt-5-mini is the special case that uses chat_completions)
101      assert result.api_mode == "codex_responses"