修正 Ollama fallback 與 PPT vision payload

tests/test_ollama_retry_chain.py

@@ -138,6 +138,31 @@ def test_generate_same_host_breaks_loop():
     assert mock_post.call_count == 1
 
 
+def test_generate_forces_final_fallback_when_unhealthy_ttl_expires_mid_request():
+    """長 timeout 期間 unhealthy TTL 過期時，第三輪仍應打 111 fallback。"""
+    import requests
+    from services import ollama_service as oss
+    from services.ollama_service import OllamaService
+
+    svc = OllamaService()
+    hosts = [
+        oss.OLLAMA_HOST_PRIMARY,
+        oss.OLLAMA_HOST_SECONDARY,
+        oss.OLLAMA_HOST_PRIMARY,  # 模擬 primary unhealthy mark 過期後 resolver 又選回 primary
+    ]
+
+    with patch('services.ollama_service.resolve_ollama_host', side_effect=hosts), \
+         patch('services.ollama_service.requests.post',
+               side_effect=requests.Timeout('all timeout')) as mock_post:
+        resp = svc.generate('test')
+
+    posted_hosts = [call.args[0].split('/api/generate')[0] for call in mock_post.call_args_list]
+    assert resp.success is False
+    assert mock_post.call_count == 3
+    assert posted_hosts == [oss.OLLAMA_HOST_PRIMARY, oss.OLLAMA_HOST_SECONDARY, oss.OLLAMA_HOST_FALLBACK]
+    assert 'all 3 hosts failed' in (resp.error or '')
+
+
 def test_generate_token_parsing_phase13():
     """Phase 13 補強：OllamaResponse 解 prompt_eval_count + eval_count"""
     from services.ollama_service import OllamaService

tests/test_ppt_vision_service.py

@@ -77,6 +77,34 @@ def test_no_issues_response(fake_image, monkeypatch):
     assert payload['images'] and isinstance(payload['images'][0], str)
 
 
+def test_check_image_compresses_valid_png_before_ollama(monkeypatch, tmp_path):
+    """有效截圖送 Ollama 前應轉成較輕的 JPEG payload。"""
+    monkeypatch.setenv('PPT_VISION_ENABLED', 'true')
+    import base64
+    Image = pytest.importorskip("PIL.Image")
+    from services.ppt_vision_service import PPTVisionService
+
+    image_path = tmp_path / 'slide.png'
+    Image.new('RGB', (1800, 1000), color=(245, 238, 226)).save(image_path)
+
+    fake_resp = MagicMock(status_code=200)
+    fake_resp.json.return_value = {'response': '✅ 無視覺異常'}
+
+    with patch('services.ollama_service.resolve_ollama_host',
+               return_value='http://test:11434'), \
+         patch('services.ollama_service.requests.post', return_value=fake_resp) as mock_post:
+        svc = PPTVisionService()
+        result = svc.check_image(str(image_path))
+
+    payload = mock_post.call_args.kwargs['json']
+    encoded = base64.b64decode(payload['images'][0])
+    assert result.success is True
+    assert encoded.startswith(b'\xff\xd8')
+    assert len(encoded) < image_path.stat().st_size
+    assert payload['options']['num_predict'] == 256
+    assert payload['keep_alive'] == '5m'
+
+
 def test_issues_detected(fake_image, monkeypatch):
     """minicpm-v 回多個 ⚠️ marker → issues_found 應含解析的問題"""
     monkeypatch.setenv('PPT_VISION_ENABLED', 'true')