import unittest
from app import create_app, db
from app.models import User, Role

class FlaskClientTestCase(unittest.TestCase):
    def setUp(self):
        self.app = create_app('testing')
        self.app_context = self.app.app_context()
        self.app_context.push()
        db.create_all()
        Role.insert_roles()
        self.client = self.app.test_client(use_cookies=True)
      
    def teardown(self):
        db.session.remove()
        db.drop_all()
        self.app_context.pop()
        
    def test_home_page(self):
        response = self.client.get(url_for('main.index'))
        self.assertTrue('Stranger' in response.get_data(as_text=True))
  

Create test_client.py