diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 8b91797..04bb6d1 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -17,11 +17,6 @@ jobs:
         uses: actions/setup-python@v3
         with:
           python-version: "3.10.10"
-      - id: 'auth'
-        name: 'Authenticate to Google Cloud'
-        uses: 'google-github-actions/auth@v1'
-        with:
-          credentials_json: '${{ secrets.GOOGLE_CREDENTIALS }}'
       - name: Install dependencies
         run: | 
           make install-poetry
diff --git a/tests/conftest.py b/tests/conftest.py
index 8ff7b2f..0843bb7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,9 +1,11 @@
 import asyncio
 import typing
 from dataclasses import dataclass
+from unittest.mock import patch
 
 import pytest
 from aioresponses import aioresponses
+from langchain_community.llms.fake import FakeListLLM
 
 from allms.domain.configuration import (
     AzureOpenAIConfiguration, AzureSelfDeployedConfiguration, VertexAIConfiguration, VertexAIModelGardenConfiguration)
@@ -25,59 +27,70 @@ class GenerativeModels:
     vertex_palm: typing.Optional[VertexAIPalmModel] = None
 
 
+class VertexAIMock(FakeListLLM):
+    def __init__(self, *args, **kwargs):
+        super().__init__(responses=["{}"])
+
+
 @pytest.fixture(scope="function")
 def models():
     event_loop = asyncio.new_event_loop()
-    return {
-        "azure_open_ai": AzureOpenAIModel(
-            config=AzureOpenAIConfiguration(
-                api_key="dummy_api_key",
-                base_url=AzureOpenAIEnv.OPENAI_API_BASE,
-                api_version=AzureOpenAIEnv.OPENAI_API_VERSION,
-                deployment=AzureOpenAIEnv.OPENAI_DEPLOYMENT_NAME,
-                model_name="gpt-4"
-            ),
-            event_loop=event_loop
-        ),
-        "vertex_palm": VertexAIPalmModel(
-            config=VertexAIConfiguration(
-                cloud_project="dummy-project-id",
-                cloud_location="us-central1"
-            ),
-            event_loop=event_loop
-        ),
-        "vertex_gemini": VertexAIGeminiModel(
-            config=VertexAIConfiguration(
-                cloud_project="dummy-project-id",
-                cloud_location="us-central1"
-            ),
-            event_loop=event_loop
-        ),
-        "vertex_gemma": VertexAIGemmaModel(
-            config=VertexAIModelGardenConfiguration(
-                cloud_project="dummy-project-id",
-                cloud_location="us-central1",
-                endpoint_id="dummy-endpoint-id"
-            ),
-            event_loop=event_loop
-        ),
-        "azure_llama2": AzureLlama2Model(
-            config=AzureSelfDeployedConfiguration(
-                api_key="dummy_api_key",
-                endpoint_url="https://dummy-endpoint.dummy-region.inference.ml.azure.com/score",
-                deployment="dummy_deployment_name"
-            ),
-            event_loop=event_loop
-        ),
-        "azure_mistral": AzureMistralModel(
-            config=AzureSelfDeployedConfiguration(
-                api_key="dummy_api_key",
-                endpoint_url="https://dummy-endpoint.dummy-region.inference.ml.azure.com/score",
-                deployment="dummy_deployment_name"
-            ),
-            event_loop=event_loop
-        )
-    }
+
+    with (
+        patch("allms.models.vertexai_palm.CustomVertexAI", VertexAIMock),
+        patch("allms.models.vertexai_gemini.CustomVertexAI", VertexAIMock),
+        patch("allms.models.vertexai_gemma.VertexAIModelGardenWrapper", VertexAIMock)
+    ):
+        return {
+                "azure_open_ai": AzureOpenAIModel(
+                    config=AzureOpenAIConfiguration(
+                        api_key="dummy_api_key",
+                        base_url=AzureOpenAIEnv.OPENAI_API_BASE,
+                        api_version=AzureOpenAIEnv.OPENAI_API_VERSION,
+                        deployment=AzureOpenAIEnv.OPENAI_DEPLOYMENT_NAME,
+                        model_name="gpt-4"
+                    ),
+                    event_loop=event_loop
+                ),
+                "vertex_palm": VertexAIPalmModel(
+                    config=VertexAIConfiguration(
+                        cloud_project="dummy-project-id",
+                        cloud_location="us-central1"
+                    ),
+                    event_loop=event_loop
+                ),
+                "vertex_gemini": VertexAIGeminiModel(
+                    config=VertexAIConfiguration(
+                        cloud_project="dummy-project-id",
+                        cloud_location="us-central1"
+                    ),
+                    event_loop=event_loop
+                ),
+                "vertex_gemma": VertexAIGemmaModel(
+                    config=VertexAIModelGardenConfiguration(
+                        cloud_project="dummy-project-id",
+                        cloud_location="us-central1",
+                        endpoint_id="dummy-endpoint-id"
+                    ),
+                    event_loop=event_loop
+                ),
+                "azure_llama2": AzureLlama2Model(
+                    config=AzureSelfDeployedConfiguration(
+                        api_key="dummy_api_key",
+                        endpoint_url="https://dummy-endpoint.dummy-region.inference.ml.azure.com/score",
+                        deployment="dummy_deployment_name"
+                    ),
+                    event_loop=event_loop
+                ),
+                "azure_mistral": AzureMistralModel(
+                    config=AzureSelfDeployedConfiguration(
+                        api_key="dummy_api_key",
+                        endpoint_url="https://dummy-endpoint.dummy-region.inference.ml.azure.com/score",
+                        deployment="dummy_deployment_name"
+                    ),
+                    event_loop=event_loop
+                )
+            }
 
 
 @pytest.fixture