CI for Node

[venitahagerty]

New branch created

[github-learning-lab]

Templated workflow success!

Great job adding the templated workflow. Adding that file to this branch is enough for GitHub Actions to begin running CI on your repository. This takes a couple of minutes, so let's take this opportunity to learn about some of the components of the workflow file you just added. We'll dive deeper into some of the key elements of this file in future steps of the course.

Step 2: Run a templated workflow

I'll respond when GitHub Actions finishes running the workflow. You can follow along in the Actions tab, or by clicking Details on the pending status below.

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Actions workflow not running? Click here

When a GitHub Actions workflow is running, you should see some checks in progress, like the screenshot below.

If the checks don't appear or if the checks are stuck in progress, there's a few things you can do to try and trigger them:

• Refresh the page, it's possible the workflow ran and the page just hasn't been updated with that change
• Try making a commit on this branch. Our workflow is triggered with a push event, and committing to this branch will result in a new push
• Edit the workflow file on GitHub and ensure there are no red lines indicating a syntax problem

[github-learning-lab]

'on:'

The on: field is what tells GitHub Actions when to run. In this case, we're running the workflow anytime there's a push.

To learn more about the fields discussed here, see:

• Workflow syntax for GitHub Actions: on: on GitHub Help
• Events that trigger workflows on GitHub Help

[github-learning-lab]

Jobs

The jobs: block defines the core component of an Actions workflow. Workflows are made of jobs, and our template workflow defines a single job with the identifier build.

Every job also needs a specific host machine on which to run, the runs-on: field is how we specify it. The template workflow is running the build job in the latest version of Ubuntu, a Linux-based operating system.

To learn more about the fields discussed here, see:

• Workflow syntax for GitHub Actions: jobs: on GitHub Help
• Workflow syntax for GitHub Actions: jobs.<job_id>: on GitHub Help
• Workflow syntax for GitHub Actions: jobs.<job_id>.runs-on: on GitHub Help
• Virtual environments for GitHub Actions on GitHub Help
• Ubuntu on Wikipedia

[github-learning-lab]

Vocabulary

Workflows, steps, actions, and jobs

Let's dig into the vocabulary of GitHub Actions.

• Workflow: A workflow is a unit of automation from start to finish, including the definition of what triggers the automation, what environment or other aspects should be taken account during the automation, and what should happen as a result of the trigger.
• Job: A job is a section of the workflow, and is made up of one or more steps. In this section of our workflow, the template defines the steps that make up the build job.
• Step: A step represents one effect of the automation. A step could be defined as a GitHub Action, or another unit, like printing something to the console.
• Action: A GitHub Action is a piece of automation written in a way that is compatible with workflows. Actions can be written by GitHub, by the open source community, or you can write them yourself!

What is checkout?

The power of GitHub Actions lies in access to actions written by the ✨ GitHub community. Here, we'll use two Actions officially written and supported by GitHub:

• actions/checkout@v2 is used to ensure our virtual machine has a copy of our codebase. The checked out code will be used to run tests against.
• actions/setup-node@v1 is used to set up proper versions of Node.js since we'll be performing testing against multiple versions.

To learn more about the fields discussed here, see:

• Workflow syntax for GitHub Actions: jobs.<job_id>.steps: on GitHub Help
• Referencing actions in your workflow on GitHub Help
• Source repository for the actions/checkout action
• Source repository for the actions/setup-node action

[github-learning-lab]

'run:'

In addition to running pre-built actions, the workflow can also execute commands, just as you would if you had direct access to the virtual machine. In this portion of the template workflow, we run some common commands relevant to Node.js projects, like npm install to install dependencies and npm test to run the chosen testing framework.

To learn more about the fields discussed here, see:

• Workflow syntax for GitHub Actions: jobs.<job_id>.steps.run: on GitHub Help
• npm install on the npm Documentation
• npm run on the npm Documentation
• npm test on the npm Documentation

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If you don't see an explanation of your CI logs below when the workflow has executed, refresh this page.

[github-learning-lab]

Running - and failing - workflow

The workflow ran! But it failed 😭. But, that's OK. Every time CI fails, it's an opportunity to learn from what's causing it. By running CI with GitHub Actions, we have access to the logs for the attempted build. These are found:

• In the Actions tab
• In the merge box for this pull request, by clicking on "Details".

If you navigate over to the build logs, you may notice that the error is "No tests found".

Learning how to read build logs and isolate the cause of the problem is an art on its own. We'll try and cover some of the basics here. In our case, the source of the error is the npm test command. The npm test command looks for a testing framework. We want to use Jest, as we mentioned earlier. Jest requires unit tests in a directory named __test__. A __test__ directory doesn't exist on this branch.

Step 3: Add your first test

Not to worry, I've got you covered! Navigate to the open pull request titled Add Jest tests and merge it into this branch. That'll get us the test files we need. I'll respond when you merge the Add Jest tests pull request into this branch.

⌨️ Activity: Add your first test script for CI to pick up

1. Navigate to the open pull request titled Add Jest tests
2. Merge the pull request

[github-learning-lab]

Waiting on tests

Great! Now that the testing framework is properly configured, we should get a response from it soon. This time, you'll practice reading the logs on your own. Just like before, you can follow along as GitHub Actions runs your job by going to the Actions tab or by clicking on "Details" in the merge box below.

When the tests finish, you'll see a red X ❌ or a green check mark ✔️ in the merge box. At that point, you'll have access to logs for the build job and its associated steps.

Step 4: Read an Actions log

By looking at the logs, can you identify which tests failed? To find it, go to one of the failed builds and scrolling through the log. Look for a section that lists all the unit tests. We're looking for the name of the test with an "x".

⌨️ Activity: Tell the bot which test is failing so we can fix it

1. Navigate to the log output
2. Identify a name of a failing test
3. Comment the name of the failing test here

I'll respond when you enter the name of at least one failing test. You can either copy and paste that portion of the log directly, or type the name of the test as a comment.

[venitahagerty]

Game

[github-learning-lab]

That wasn't the test name I expected, but that's alright. If you typed something slightly different than what I looked for that may explain it.

I expected one of the following test names:

• Initializes with two players
• Starts the game with a random player
• Sets the current player to be whoever it is not

Let's keep going anyway!

[github-learning-lab]

Reading failed logs

One of the failing tests is: Initializes with two players. If you dig deeper into the logs, you may notice these results in particular:

  ● Game › Game › Initializes with two players

    expect(received).toBe(expected) // Object.is equality

    Expected: "Nate"
    Received: "Bananas"

      12 |     it('Initializes with two players', async () => {
      13 |       expect(game.p1).toBe('Salem')
    > 14 |       expect(game.p2).toBe('Nate')
         |                       ^
      15 |     })
      16 | 
      17 |     it('Initializes with an empty board', async () => {

      at Object.toBe (__test__/game.test.js:14:23)

This tells us that a unit test has been written that names the two players Salem and Nate, and then checks if that name sticks. However, we get 🍌 Bananas instead of Nate! How did this happen?

To find out, it may help to know it's common practice to name test files the same as the code file they are testing, but with a .test.js extension. Therefore, we can assume that the test result from game.test.js is caused by a problem in game.js. I'll point it out below.

Make the changes suggested below. I'll respond when the workflow runs.

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Actions workflow not running? Click here

When a GitHub Actions workflow is running, you should see some checks in progress, like the screenshot below.

If the checks don't appear or if the checks are stuck in progress, there's a few things you can do to try and trigger them:

• Refresh the page, it's possible the workflow ran and the page just hasn't been updated with that change
• Try making a commit on this branch. Our workflow is triggered with a push event, and committing to this branch will result in a new push
• Edit the workflow file on GitHub and ensure there are no red lines indicating a syntax problem

[github-learning-lab]

Step 5: Fix the test

This line is causing the problem. Let's fix it by initializing this instance of p2 to the proper value.

⌨️ Activity: Edit the file that's causing the test to fail

Edit the src/game.js file directly, or accept the suggestion below.

Suggested change

	this.p2 = 'Bananas'
	this.p2 = p2

Once you commit the changes, the tests will run again and should pass. I'll respond when the tests pass. If the tests don't pass, I'll provide some troubleshooting information.

[github-learning-lab]

Great job! Go ahead and merge this pull request so your changes are automatically shared with anyone that contributes to this project.

I'll respond when you merge this pull request.

[github-learning-lab]

Let's go to the next step.