Exercise: Testing the Application

In this exercise, you will return to the AWS Cloud9 instance and run the local build for the project. The local build contains linting (or static analysis) of the code and unit tests. Next, you will run an integration test. The integration test finds the API Gateway Websocket endpoint, and it simulates a player completing a game. You will then add a simple feature to the code. Finally, you will fix the unit tests and commit the changes to your repository

Task 1: Running unit tests

In this task, you run unit tests against the application code. You then view the reports that are outputted from these tests.

1. In your AWS Cloud9 terminal, make sure you are still in the trivia-app folder. The prompt should also show the top-level Git branch.

cd ~/environment/trivia-app

2. Install the backend code requirements and the unit test requirements by using pip3 to run the following commands.

pip3 install -U -r back-end-python/gameactions/requirements.txt
pip3 install -U -r back-end-python/tests/requirements.txt
./local_build.sh

You should see the code rating after pylint does its static analysis:

------------------------------------
Your code has been rated at 10.00/10

Then, pytest runs its unit tests, which are shown like the following example:

back-end-python/tests/unit/test_handler.py .........

It will also output a coverage report in HTML, which is in /trivia-app/htmlcov.

3. In the htmlcov folder, right-click the index.html file and view the coverage report by choosing Preview.

Task 2: Running the integration test

For this task, you run an integration test against the application code.

1. Start the integration test (which will simulate a game) by running the following command.

AWS_SAM_STACK_NAME=trivia-app pytest -s back-end-python/tests/integration/test_api_gateway.py

The integration test uses the AWS SAM stack to find the Websocket endpoint, so the stack is passed in the AWS_SAM_STACK_NAME environment variable.

At the end of the test, you should see the following message: 1 passed

Task 3: Updating the code and unit tests

In this task, you update the application code to change the score value from 10 to 20. You also update the unit test code.

1. Open the trivia-app/back-end-python/gameactions/app.py file.
2. Scroll down to the trivia_calculate_scores function.
3. Update the code so the game increments the score by 20 instead of by 10. Locate score += 10 and change it to score += 20. Make sure to save the file.

score += 20

4. Verify that you left the code in a stable state by running the ./local_build.sh command.

At the top of the failure report, you should see that the test_trivia_calculate_scores_correct test failed:

=============================================== FAILURES ============================================================================================
_________________________________ test_trivia_calculate_scores_correct ______________________________________________________________________________

You also need to update the unit test to match the new score.

5. Open the trivia-app/back-end-python/tests/unit/test_handler.py file.

6. Find the test_trivia_calculate_scores_correct function.

7. In the function’s TABLE.update_item.assert_called_with call, find the AttributeUpdates field and update the Value from 10 to 20.

AttributeUpdates={'score': {'Value': 20, 'Action': 'PUT'}}

8. You must also update app.MANAGEMENT.post_to_connection.assert_has_calls (which tests API Gateway Websocket calls). Change the value of score from 10 to 20.

mock.call(Data='{"action": "playerlist", "players": [{"connectionId": "connection-1", "playerName": "AliceBlue", "score": 20, "currentPlayer": true}]}', ConnectionId='connection-1'),

9. Save the file and re-run ./local_build.sh. The test summary should again show that everything passed.

Task 4: Committing to source control through the AWS Cloud9 GUI or the AWS CLI

In this task, you commit the changes from the previous tasks to your code repository. You can commit the code by using either the AWS Cloud9 GUI, or AWS CLI commands in the AWS Cloud9 terminal.

1. In the menu, at the left of AWS Cloud9, choose the source control icon:

2. Under Changes, select either the app.py or test_handler.py file to view the diffs between the original files and your changes.

3. Under Changes, stage the changes in app.py and test_handler.py for a commit by placing the pointer over the file name and choosing the stage icon (+) for the file. The files should now appear under Staged Changes.

4. In the Source Control pane, at the right side of the trivia-app heading, left-click paper scroll icon and choose Commit. Choose Yes.

5. Under the trivia-app heading, enter the following commit message and press Enter: Scores now increment by 20

6. In the trivia-app heading, left-click the paper scroll icon and choose Push to…. When prompted to select a remote, choose the remote named origin.

Commit changes through the AWS CLI