part60-eng.md

How to skip test in Go and config test flag in VS Code

Original video

Hello guys, welcome to the backend master class. In previous lecture, we've written a test to send emails with Gmail. However, if we keep the test like this, it will be run every time the GitHub CI test workflow is triggered. Because in the workflow, we're using the "make test" command to run all tests in the project.

      - name: Run migrations
        run: make migrateup

      - name: Test
        run: make test

And whenever this command is run, the TestSendEmail will also be executed, and a new email will be delivered.

This is really not something we want, because there would be a lot of spam emails in the inbox.

So how can we skip only this test while still keeping the others?

How to skip test in Go

Well, there's a very simple way to do that, using the -short flag.

At the beginning of the test, we can check if testing.Short() is true. If it is, then it means that the -short flag has been set. And if that's the case, this means we're telling Go that we only want to run "short" tests, or in other words, the tests that don't take a long time to run. So, we should skip all tests that we think might be slow. We can easily do that by calling the t.Skip() function.

func TestSendEmailWithGmail(t *testing.T) {
    if testing.Short() {
        t.Skip()
    }
    
    config, err := util.LoadConfig("..")
    ...
}

With this change, the SendEmail test won't be executed if the short flag is set. So what we need to do now is: open the Makefile, and add the -short flag to the test command.

...

test:
	go test -v -cover -short ./...

...

Pretty simple, right?

Alright, now if we run

make test

in the terminal, we'll see a log here saying that the SendEmail test is skipped.

=== RUN   TestSendEmailWithGmail
    sender_test.go:12: 
--- SKIP: TestSendEmailWithGmail (0.00s)
PASS

And of course, there will be no new emails delivered to our inbox.

So it works! Excellent!

Note that, the change we just made doesn't affect how we develop and test the feature in VS Code. We can still run the test here,

and the test is not skipped,

because by default, the -short flag is not set.

And so, a new email will still be delivered to our inbox, just as expected.

You can also change the behaviour of the test command in VS Code if you want.

Config test flag in VS Code

Just open the Settings page in Code menu, and search for go test flag.

If you've installed the Go extension, you will see the Test Flags section at the bottom.

This is where you can config the flags you want to pass into the go test command.

Let's click "Edit in settings.json". It will bring you to the go.testFlag section. Here I have defined 2 flags for my test command.

{
    ...
    "extensions.ignoreRecommendations": false,
    "go.testFlags": [
        
        "-v",
        "-count=1"
    ],
    ...
}

The first one is the "-v" flag, which means "verbose". Normally Go only prints out the logs if the test failed. But with the verbose flag enabled, it will always print out the logs, even if the test passed.

The second flag I set here is "-count=1". With this flag, I want to disable the test caching feature, so my test will always run when I click the Run test button, even if there's no change in the code or the test.

You can also add the -short flag here if you want,

{
    ...
    "extensions.ignoreRecommendations": false,
    "go.testFlags": [
        "-short",
        "-v",
        "-count=1"
    ],
    ...
}

but I think it's better to not add it here, because when developing the feature, we will always want to run the test, not skip it.

Alright, that's all I wanted to share with you in this video.

It was pretty short, but I hope it was still interesting and useful for you.

Thanks a lot for watching. Happy learning, and see you in the next lecture!