Test Voting

In this article, we set up and run tests for the voting functionality in your application. Our tests cover various scenarios including successful voting, duplicate vote attempts, vote deletions, and edge cases such as voting on non-existent posts or by unauthorized users. Before running these tests, ensure you have an authorized client and properly configured test posts in your test environment.

Retrieving and Validating Posts

The initial test function retrieves all posts and validates them using the defined schema. This ensures that the posts returned by the API match the expected structure.

import pytest
from app import schemas

def test_get_all_posts(authorized_client, test_posts):
    res = authorized_client.get("/posts/")

    def validate(post):
        return schemas.PostOut(**post)
    
    posts_list = list(map(validate, res.json()))
    
    assert len(res.json()) == len(test_posts)
    assert res.status_code == 200

Console Output:

venv\lib\site-packages\aiofiles\os.py:10
venv\lib\site-packages\aiofiles\os.py:10
venv\lib\site-packages\aiofiles\os.py:10
venv\lib\site-packages\aiofiles\os.py:10
C:\Users\sanje\Documents\courses\fastapi\venv\lib\site-packages\aiofiles\os.py:10: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead
=========== 4 passed, 5 warnings in 2.17s ===========

Save this file as test_votes.py.

Testing a Successful Vote

For the successful vote test, we simulate voting on a post. Initially, the function prototype is set as follows:

def test_vote_on_post(authorized_client, test_post)

After setting up the endpoint URL and required data (post ID and vote direction), we update the test to include the correct post ID:

def test_vote_on_post(authorized_client, test_posts):
    # Vote on the first post by sending the post's id
    authorized_client.post("/vote/", json={"post_id": test_posts[0].id})

Since a vote direction is needed (with 1 representing a like/upvote), the function is modified accordingly:

def test_vote_on_post(authorized_client, test_posts):
    # Vote on the first post with direction set to 1 (like/upvote)
    authorized_client.post("/vote/", json={"post_id": test_posts[0].id, "dir": 1})

In our final version, we simulate voting on a post owned by another user by selecting the fourth post from the list:

def test_vote_on_post(authorized_client, test_posts):
    res = authorized_client.post("/vote/", json={"post_id": test_posts[3].id, "dir": 1})
    assert res.status_code == 201

Console Output after running:

C:\users\sanje\documents\courses\fastapi\venv\lib\site-packages\aiofiles\os.py:10: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead

Running the command:

pytest tests/test_posts.py -v -s

yields:

=================================== test session starts ====================================
...
4 passed, 5 warnings in 2.17s

Testing Duplicate Voting

Duplicate voting is an important scenario where a user attempts to vote on a post twice. First, a fixture is used to set up the initial vote:

import pytest
from app import models

@pytest.fixture()
def test_vote(test_posts, session, test_user):
    new_vote = models.Vote(post_id=test_posts[3].id, user_id=test_user['id'])
    session.add(new_vote)
    session.commit()

The test case for duplicate voting validates that the second vote attempt returns a 409 status code:

def test_vote_twice_post(authorized_client, test_posts, test_vote):
    res = authorized_client.post("/vote/", json={"post_id": test_posts[3].id, "dir": 1})
    assert res.status_code == 409

Testing Vote Deletion

Vote deletion is triggered by setting the vote direction to 0. This function sends the deletion request and asserts a successful deletion:

def test_delete_vote(authorized_client, test_posts, test_vote):
    res = authorized_client.post("/vote/", json={"post_id": test_posts[3].id, "dir": 0})
    assert res.status_code == 201

To ensure proper error handling, the following test verifies that deleting a non-existent vote returns a 404 status code. Here, the test_vote fixture is not used so no vote exists for the given post:

def test_delete_vote_non_exist(authorized_client, test_posts):
    res = authorized_client.post("/vote/", json={"post_id": test_posts[3].id, "dir": 0})
    assert res.status_code == 404

Testing Voting on a Non-Existent Post

When a user attempts to vote on a post that does not exist (using an ID that isn’t in the database), the API should return a 404 status code. The following test case ensures this behavior:

def test_vote_post_non_exist(authorized_client, test_posts):
    res = authorized_client.post("/vote/", json={"post_id": 80000, "dir": 1})
    assert res.status_code == 404

Testing Unauthorized Voting

To verify security measures, the final voting test checks that an unauthorized user (i.e., using an unauthenticated client) cannot vote. This test should return a 401 status code:

def test_vote_unauthorized_user(client, test_posts):
    res = client.post("/vote/", json={"post_id": test_posts[3].id, "dir": 1})
    assert res.status_code == 401

Console output when running these tests might display warnings such as:

venv\lib\site-packages\aiofiles\os.py:10: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead

Additional Tests for Bank Account Operations

Although not directly related to voting tests, the repository also includes tests for bank account operations. An example from the bank account test file is given below:

def test_bank_default_amount(zero_bank_account):
    print("Testing my bank account")
    assert zero_bank_account.balance == 0

def test_withdraw(bank_account):
    bank_account.withdraw(20)
    assert bank_account.balance == 30

The output confirms that the tests pass:

6 passed, 5 warnings in 3.25s

Final Notes

Before deleting the database.py file, ensure that all tests pass by running your complete test suite. The majority of functionality has now been moved to conftest.py.

An example of the test_posts fixture used throughout the tests is shown below:

@pytest.fixture
def test_posts(test_user, session, test_user2):
    posts_data = [
        {
            "title": "first title",
            "content": "first content",
            "owner_id": test_user['id']
        },
        {
            "title": "2nd title",
            "content": "2nd content",
            "owner_id": test_user['id']
        },
        {
            "title": "3rd title",
            "content": "3rd content",
        },
    ]

When writing tests, consider additional scenarios that could potentially break the application by creating individual test cases for each situation. Comprehensive testing is essential for ensuring the stability and reliability of your application.

By following this guide, you have now set up a robust test suite covering various edge cases and scenarios for voting and other functionality. This comprehensive approach not only helps in maintaining functionality but also enhances the resilience of your application.

Introduction

Python Setup

FastAPI Basics

Working with Databases

Databases with Python

Advanced FastAPI

Database Migration

Deployment

Testing

CI/CD

Retrieving and Validating Posts

Testing a Successful Vote

Testing Duplicate Voting

Testing Vote Deletion

Testing Voting on a Non-Existent Post

Testing Unauthorized Voting

Additional Tests for Bank Account Operations

Final Notes

Watch Video

​Retrieving and Validating Posts

​Testing a Successful Vote

​Testing Duplicate Voting

​Testing Vote Deletion

​Testing Voting on a Non-Existent Post

​Testing Unauthorized Voting

​Additional Tests for Bank Account Operations

​Final Notes

Watch Video

Retrieving and Validating Posts

Testing a Successful Vote

Testing Duplicate Voting

Testing Vote Deletion

Testing Voting on a Non-Existent Post

Testing Unauthorized Voting

Additional Tests for Bank Account Operations

Final Notes