diff --git a/.github/workflows/aws-preview.yml b/.github/workflows/aws-preview.yml
index 46b6cae8..40992023 100644
--- a/.github/workflows/aws-preview.yml
+++ b/.github/workflows/aws-preview.yml
@@ -1,5 +1,10 @@
 name: Deploy Backend to Preview ECS
 
+# on:
+#   workflow_run:
+#     workflows: ["PR Tests"]
+#     types:
+#       - completed
 on:
   pull_request:
     branches: [ "main" ]
@@ -17,11 +22,12 @@ env:
 permissions:
   id-token: write   # This is required for requesting the JWT
   contents: read    # This is required for actions/checkout
+  actions: write 
 
 jobs:
   deploy:
     runs-on: ubuntu-latest
-    environment: production
+    environment: Preview
     strategy:
       fail-fast: true
 
diff --git a/.github/workflows/pr-tests.yml b/.github/workflows/pr-tests.yml
new file mode 100644
index 00000000..d145c8b9
--- /dev/null
+++ b/.github/workflows/pr-tests.yml
@@ -0,0 +1,66 @@
+name: PR Tests
+
+on:
+  pull_request:
+    branches: [ "main" ]
+    paths:
+      - .github/workflows/aws-preview.yml
+      - server/**
+      - petercat_utils/**
+      - subscriber/**
+
+permissions:
+  id-token: write   # This is required for requesting the JWT
+  contents: read    # This is required for actions/checkout
+  pull-requests: write 
+  actions: write
+
+env:
+  AWS_REGION: ap-northeast-1
+  REPORT_FILE: md_report.md
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    environment: Preview
+    strategy:
+      fail-fast: true
+    defaults:
+      run:
+        working-directory: ./server
+    steps:
+      - name: Checkout
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          role-to-assume: arn:aws:iam::654654285942:role/Github-OIDC
+          audience: sts.amazonaws.com
+          aws-region: ${{ env.AWS_REGION }}
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12.0'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          pip install ruff
+          pip install pytest pytest-cov pytest-md-report
+        
+      - name: Lint with Ruff
+        run: |
+          ruff check --output-format=github .
+
+      - name: Test with pytest
+        run: |
+          pytest -v --md-report --md-report-output ${{ env.REPORT_FILE }}
+          cat ${{ env.REPORT_FILE }}
+      
+      - name: Comment PR
+        uses: thollander/actions-comment-pull-request@v2
+        with:
+          filePath: ./server/${{ env.REPORT_FILE }}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index b30bf697..717b791f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@ venv
 .next/
 out/
 
+.ruff_cache/
 
 # production
 build
diff --git a/Makefile b/Makefile
deleted file mode 100644
index 9c30432a..00000000
--- a/Makefile
+++ /dev/null
@@ -1,25 +0,0 @@
-test:
-	pytest backend/tests
-
-dev:
-	docker compose -f docker/docker-compose.yml build backend-core
-	docker compose -f docker/docker-compose.yml up --build -d
-
-dev-ps:
-	docker compose -f docker/docker-compose.yml ps
-
-dev-init:
-	rm -rf docker/volumes/db/data 
-	docker compose -f docker/docker-compose.yml build backend-core
-	docker compose -f docker/docker-compose.yml up --build
-
-prod:
-	docker compose build backend-core
-	docker compose -f docker-compose.yml up --build
-
-test-type:
-	@if command -v python3 &>/dev/null; then \
-		python3 -m pyright; \
-	else \
-		python -m pyright; \
-	fi
diff --git a/client/tests/github/pull_request_test.py b/client/tests/github/pull_request_test.py
deleted file mode 100644
index d60b0e69..00000000
--- a/client/tests/github/pull_request_test.py
+++ /dev/null
@@ -1,13 +0,0 @@
-import pytest  
-import json
-import os
-
-from server.event_handler.pull_request import PullRequestEventHandler
-
-def test_event_handler():
-    filepath = os.path.join(os.path.dirname(__file__), 'pull_request_event.json')
-    with open(filepath) as ev:
-        event = json.load(ev)
-        handler = PullRequestEventHandler(payload = event, access_token="123")
-        result = handler.execute()
-        assert result["success"] == True
diff --git a/docs/guides/self_hosting_aws.md b/docs/guides/self_hosting_aws.md
index e69de29b..e1517df3 100644
--- a/docs/guides/self_hosting_aws.md
+++ b/docs/guides/self_hosting_aws.md
@@ -0,0 +1,25 @@
+## Supabase Budget
+
+|Resources| Instances | Pricing |
+|---------|------|------|
+| Supabase   |   1   | $0
+
+
+## Infrastructure Budget
+
+|Resources| Instances | Pricing |
+|---------|------|------|
+| EC2 Container Registry (ECR)   |      | https://aws.amazon.com/cn/ecr/pricing/
+| Route 53 | 1 | $0.53
+| Secrets Manager | 1 | $0.40
+| S3 | Very Few | https://aws.amazon.com/cn/s3/pricing/
+| CloudFront | 2 | $0
+| Lambda | 4 | https://aws.amazon.com/cn/lambda/pricing/
+
+
+## LLM Budget
+
+|Resources| Instances | Pricing |
+|---------|------|------|
+| OpenAI   |  -    | https://openai.com/pricing/
+| Gemini flash | - | $0
diff --git a/petercat_utils/rag_helper/task.py b/petercat_utils/rag_helper/task.py
index fd26995b..e73bee7f 100644
--- a/petercat_utils/rag_helper/task.py
+++ b/petercat_utils/rag_helper/task.py
@@ -1,5 +1,6 @@
 import json
 from typing import Optional
+from github import Github
 
 import boto3
 
@@ -7,15 +8,14 @@
 from .git_issue_task import GitIssueTask
 from .git_task import GitTask
 
-# Create SQS client
-sqs = boto3.client("sqs")
-
-from github import Github
-
 from ..utils.env import get_env_variable
 from ..data_class import TaskStatus, TaskType
 from ..db.client.supabase import get_client
 
+# Create SQS client
+sqs = boto3.client("sqs")
+
+
 g = Github()
 
 TABLE_NAME = "rag_tasks"
diff --git a/pyproject.toml b/pyproject.toml
index 808ee806..ee604801 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,11 +6,26 @@ authors = ["raoha.rh <raohai.rh@antgroup.com>"]
 readme = "README.md"
 packages = [{include = "petercat_utils"}]
 
+[tool.ruff]
+builtins = ["_"]
+
+[pytest]
+testpaths = ["tests"]
+pythonpath = "."
+consider_namespace_packages = "True"
+python_files = "test_*.py"
+cov="com"
+cov-report=["xml","html"]
+md_report = true
+md_report_verbose = 0
+md_report_color = "auto"
+
 [tool.poetry.dependencies]
 python = "^3.8"
 langchain_community = "^0.2.11"
 langchain_openai = "^0.1.20"
 langchain_core = "0.2.28"
+langchain = "^0.2.12"
 supabase = "2.6.0"
 pydantic = "2.7.0"
 PyGithub = "2.3.0"
diff --git a/server/agent/bot_builder.py b/server/agent/bot_builder.py
index fbeb9b76..339873ba 100644
--- a/server/agent/bot_builder.py
+++ b/server/agent/bot_builder.py
@@ -1,5 +1,6 @@
 from typing import AsyncIterator, Optional
 from petercat_utils.data_class import ChatData
+
 from agent.base import AgentBuilder
 from prompts.bot_builder import generate_prompt_by_user_id
 from tools import bot_builder
diff --git a/server/agent/qa_chat.py b/server/agent/qa_chat.py
index c55ba53b..1be7d8f9 100644
--- a/server/agent/qa_chat.py
+++ b/server/agent/qa_chat.py
@@ -1,8 +1,9 @@
 from typing import AsyncIterator, Optional
-from agent.base import AgentBuilder
-from prompts.bot_template import generate_prompt_by_repo_name
 from petercat_utils import get_client
 from petercat_utils.data_class import ChatData
+
+from agent.base import AgentBuilder
+from prompts.bot_template import generate_prompt_by_repo_name
 from tools import issue, sourcecode, knowledge, git_info
 
 
diff --git a/server/auth/get_user_info.py b/server/auth/get_user_info.py
index 92aa3aad..7198ad98 100644
--- a/server/auth/get_user_info.py
+++ b/server/auth/get_user_info.py
@@ -1,5 +1,5 @@
 from typing import Annotated
-from fastapi import Cookie, HTTPException
+from fastapi import Cookie
 import httpx
 import secrets
 import random
@@ -8,7 +8,8 @@
 from .get_oauth_token import get_oauth_token
 from petercat_utils import get_client, get_env_variable
 
-random_str = lambda N: ''.join(random.SystemRandom().choice(string.ascii_uppercase + string.ascii_lowercase + string.digits) for _ in range(N))
+def random_str(N):
+    return ''.join(random.SystemRandom().choice(string.ascii_uppercase + string.ascii_lowercase + string.digits) for _ in range(N))
 
 AUTH0_DOMAIN = get_env_variable("AUTH0_DOMAIN")
 
@@ -70,7 +71,7 @@ async def get_user_id(petercat_user_token: Annotated[str | None, Cookie()] = Non
         user_info = await getUserInfoByToken(petercat_user_token)
         return user_info['id']
 
-    except Exception as e:
+    except Exception:
         return None
 
 async def get_user_access_token(petercat_user_token: Annotated[str | None, Cookie()] = None):
@@ -83,5 +84,5 @@ async def get_user_access_token(petercat_user_token: Annotated[str | None, Cooki
         access_token = await getUserAccessToken(user_id=user_info['id'])
         print(f"get_user_access_token: user_info={user_info}, access_token={access_token}")
         return access_token
-    except Exception as e:
+    except Exception:
         return None
diff --git a/server/bot/builder.py b/server/bot/builder.py
index 075e2776..35603ac8 100644
--- a/server/bot/builder.py
+++ b/server/bot/builder.py
@@ -4,6 +4,7 @@
 from petercat_utils import get_client
 from petercat_utils.data_class import RAGGitDocConfig
 from petercat_utils import git_doc_task
+
 from prompts.bot_template import generate_prompt_by_repo_name
 
 g = Github()
diff --git a/server/dao/authorizationDAO.py b/server/dao/authorizationDAO.py
index 90dbe98f..9fff5100 100644
--- a/server/dao/authorizationDAO.py
+++ b/server/dao/authorizationDAO.py
@@ -1,10 +1,9 @@
+from supabase.client import Client
+
+from petercat_utils.db.client.supabase import get_client
 
-import json
 from dao.BaseDAO import BaseDAO
 from models.authorization import Authorization
-from supabase.client import Client, create_client
-
-from petercat_utils.db.client.supabase import get_client
 
 class AuthorizationDAO(BaseDAO):
     client: Client
diff --git a/server/event_handler/discussion.py b/server/event_handler/discussion.py
index f5061d63..d0f8648d 100644
--- a/server/event_handler/discussion.py
+++ b/server/event_handler/discussion.py
@@ -2,10 +2,11 @@
 from typing import Any
 from github import Github, Auth
 from github import GithubException
-from agent.qa_chat import agent_chat
 
 from petercat_utils.data_class import ChatData, Message, TextContentBlock
 
+from agent.qa_chat import agent_chat
+
 
 class DiscussionEventHandler:
     event: Any
diff --git a/server/event_handler/issue.py b/server/event_handler/issue.py
index 322c4689..3485fde3 100644
--- a/server/event_handler/issue.py
+++ b/server/event_handler/issue.py
@@ -1,10 +1,11 @@
 from typing import Any
 from github import Github, Auth
 from github import GithubException
-from agent.qa_chat import agent_chat
 
 from petercat_utils.data_class import ChatData, Message, TextContentBlock
 
+from agent.qa_chat import agent_chat
+
 
 class IssueEventHandler:
     event: Any
diff --git a/server/main.py b/server/main.py
index fb151903..80748ea4 100644
--- a/server/main.py
+++ b/server/main.py
@@ -1,6 +1,4 @@
-import os
 
-import uvicorn
 from fastapi import FastAPI
 from starlette.middleware.sessions import SessionMiddleware
 from fastapi.middleware.cors import CORSMiddleware
@@ -10,6 +8,7 @@
 
 # Import fastapi routers
 from routers import bot, health_checker, github, rag, auth, chat, task
+
 AUTH0_DOMAIN = get_env_variable("AUTH0_DOMAIN")
 API_AUDIENCE = get_env_variable("API_IDENTIFIER")
 CLIENT_ID = get_env_variable("AUTH0_CLIENT_ID")
@@ -50,8 +49,8 @@
 app.include_router(task.router)
 
 
-if __name__ == "__main__":
-    if is_dev:
-        uvicorn.run("main:app", host="0.0.0.0", port=int(os.environ.get("PORT", "8080")), reload=True)
-    else:
-        uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("PORT", "8080")))
+# if __name__ == "__main__":
+#     if is_dev:
+#         uvicorn.run("main:app", host="0.0.0.0", port=int(os.environ.get("PORT", "8080")), reload=True)
+#     else:
+#         uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("PORT", "8080")))
diff --git a/server/models/authorization.py b/server/models/authorization.py
index c75423bd..f517c947 100644
--- a/server/models/authorization.py
+++ b/server/models/authorization.py
@@ -1,7 +1,7 @@
 from datetime import datetime
 import json
 from pydantic import BaseModel, field_serializer
-from typing import Any, Dict
+from typing import Dict
 
 class Authorization(BaseModel):
     token: str
diff --git a/server/pytest.ini b/server/pytest.ini
index 94a50dc0..993fa8c8 100644
--- a/server/pytest.ini
+++ b/server/pytest.ini
@@ -1,3 +1,7 @@
 [pytest]
 testpaths = tests
-python_files = test_*.py
\ No newline at end of file
+rootdir=server
+consider_namespace_packages = True
+python_files = test_*.py
+cov=com
+cov-report=xml,html
diff --git a/server/requirements.txt b/server/requirements.txt
index a2c0e7c3..a8ccc8dd 100644
--- a/server/requirements.txt
+++ b/server/requirements.txt
@@ -4,9 +4,8 @@ python-dotenv==1.0.0
 openai
 mangum
 langserve
-langchain_community
-langchain
-langchain-openai
+langchain_community>=0.2.11
+langchain>=0.2.12
 PyGithub
 GitPython
 python-multipart
diff --git a/server/routers/__init__.py b/server/routers/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/server/routers/auth.py b/server/routers/auth.py
index 770c4647..851b4949 100644
--- a/server/routers/auth.py
+++ b/server/routers/auth.py
@@ -1,11 +1,10 @@
 from typing import Annotated
 from fastapi import APIRouter, Cookie, Request, HTTPException, status, Response
-
 from fastapi.responses import RedirectResponse
 import httpx
-
 from petercat_utils import get_client, get_env_variable
-from auth.get_user_info import generateAnonymousUser, getAnonymousUserInfoByToken, getUserAccessToken, getUserInfoByToken
+
+from auth.get_user_info import generateAnonymousUser, getAnonymousUserInfoByToken, getUserInfoByToken
 
 AUTH0_DOMAIN = get_env_variable("AUTH0_DOMAIN")
 
diff --git a/server/routers/bot.py b/server/routers/bot.py
index 755ecb58..7482fe33 100644
--- a/server/routers/bot.py
+++ b/server/routers/bot.py
@@ -1,10 +1,11 @@
 from fastapi import APIRouter, Depends, status, Query, Path
 from fastapi.responses import JSONResponse
-from auth.get_user_info import get_user_id
 from petercat_utils import get_client
+from typing import Annotated, Optional
+
+from auth.get_user_info import get_user_id
 from bot.builder import bot_builder, bot_info_generator
 from type_class.bot import BotUpdateRequest, BotCreateRequest
-from typing import Annotated, Optional
 
 router = APIRouter(
     prefix="/api/bot",
diff --git a/server/routers/chat.py b/server/routers/chat.py
index 0baaf94b..ed865b11 100644
--- a/server/routers/chat.py
+++ b/server/routers/chat.py
@@ -1,11 +1,11 @@
-import asyncio
 from typing import Annotated, Optional
-from fastapi import APIRouter, Cookie, Depends
+from fastapi import APIRouter, Depends
 from fastapi.responses import StreamingResponse
-from auth.get_user_info import get_user_access_token, get_user_id
 from petercat_utils.data_class import ChatData
+
 from agent import qa_chat, bot_builder
 from verify.rate_limit import verify_rate_limit
+from auth.get_user_info import get_user_access_token, get_user_id
 
 
 router = APIRouter(
diff --git a/server/routers/github.py b/server/routers/github.py
index 06b95661..0dc4e8e8 100644
--- a/server/routers/github.py
+++ b/server/routers/github.py
@@ -59,7 +59,7 @@ def get_app_installations_access_token(installation_id: str, jwt: str):
     return resp.json()
 
 def get_installation_repositories(access_token: str):
-    url = f"https://api.github.com/installation/repositories"
+    url = "https://api.github.com/installation/repositories"
     print("get_installation_repositories", url)
     resp = requests.get(url, headers={
         'X-GitHub-Api-Version': '2022-11-28',
diff --git a/server/routers/health_checker.py b/server/routers/health_checker.py
index 4b8ca9a2..cfd90517 100644
--- a/server/routers/health_checker.py
+++ b/server/routers/health_checker.py
@@ -1,6 +1,4 @@
-from fastapi import APIRouter, Depends
-
-from verify.rate_limit import verify_rate_limit
+from fastapi import APIRouter
 
 router = APIRouter(
     prefix="/api",
@@ -11,7 +9,3 @@
 @router.get("/health_checker")
 def health_checker():
     return { "Hello": "World" }
-
-@router.get("/login_checker", dependencies=[Depends(verify_rate_limit)])
-def login_checker():
-    return { "Hello": "World" }
\ No newline at end of file
diff --git a/server/routers/rag.py b/server/routers/rag.py
index 1806d1f4..a919f11c 100644
--- a/server/routers/rag.py
+++ b/server/routers/rag.py
@@ -3,7 +3,6 @@
 
 from fastapi import APIRouter, Depends
 from petercat_utils.db.client.supabase import get_client
-from verify.rate_limit import verify_rate_limit
 
 from petercat_utils.data_class import RAGGitDocConfig, RAGGitIssueConfig, TaskType
 from petercat_utils.rag_helper import (
@@ -14,6 +13,9 @@
     git_issue_task,
 )
 
+from verify.rate_limit import verify_rate_limit
+
+
 router = APIRouter(
     prefix="/api",
     tags=["rag"],
diff --git a/server/tests/__init__.py b/server/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/server/tests/conftest.py b/server/tests/conftest.py
new file mode 100644
index 00000000..6db85294
--- /dev/null
+++ b/server/tests/conftest.py
@@ -0,0 +1,5 @@
+# tests/conftest.py
+import sys
+import os
+
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
diff --git a/server/tests/test_main.py b/server/tests/test_main.py
new file mode 100644
index 00000000..1612d400
--- /dev/null
+++ b/server/tests/test_main.py
@@ -0,0 +1,9 @@
+from fastapi.testclient import TestClient
+from main import app
+
+client = TestClient(app)
+
+def test_health_checker():
+    response = client.get("/api/health_checker")
+    assert response.status_code == 200
+    assert response.json() == { "Hello": "World" }
diff --git a/server/tools/bot_builder.py b/server/tools/bot_builder.py
index d4ec5dcb..9f39079f 100644
--- a/server/tools/bot_builder.py
+++ b/server/tools/bot_builder.py
@@ -1,9 +1,9 @@
-import json
 from typing import List, Optional
 from fastapi.responses import JSONResponse
 from langchain.tools import tool
 from github import Github
 from petercat_utils import get_client
+
 from bot.builder import bot_builder
 
 g = Github()
diff --git a/server/utils/github.py b/server/utils/github.py
index cee13286..71a51c83 100644
--- a/server/utils/github.py
+++ b/server/utils/github.py
@@ -1,12 +1,12 @@
 from typing import Union
 import boto3
 from botocore.exceptions import ClientError
-from event_handler.pull_request import PullRequestEventHandler
-from event_handler.discussion import DiscussionEventHandler
-from event_handler.issue import IssueEventHandler
 from petercat_utils import get_env_variable
 from github import Auth
 
+from event_handler.pull_request import PullRequestEventHandler
+from event_handler.discussion import DiscussionEventHandler
+from event_handler.issue import IssueEventHandler
 
 APP_ID = get_env_variable("X_GITHUB_APP_ID")
 
diff --git a/server/verify/rate_limit.py b/server/verify/rate_limit.py
index 2a49e826..cb820378 100644
--- a/server/verify/rate_limit.py
+++ b/server/verify/rate_limit.py
@@ -2,9 +2,10 @@
 from fastapi import Cookie, HTTPException
 from datetime import datetime, timedelta
 
-from auth.get_user_info import getUserInfoByToken
 from petercat_utils import get_client, get_env_variable
 
+from auth.get_user_info import getUserInfoByToken
+
 RATE_LIMIT_ENABLED = get_env_variable("RATE_LIMIT_ENABLED", "False") == 'True'
 RATE_LIMIT_REQUESTS = get_env_variable("RATE_LIMIT_REQUESTS") or 100
 RATE_LIMIT_DURATION = timedelta(minutes=int(get_env_variable("RATE_LIMIT_DURATION") or 1))