Building data-driven web apps with Flask and SQLAlchemy Transcripts
Chapter: Testing web apps
Lecture: Getting started with tests
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Now, it's time to start writing some code
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and getting our tests in place.
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So, let's go and open our new project.
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I've copied this over
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as you can see into Chapter 14 testing.
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We're going to work here.
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Now, probably the first thing that we want to test
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is this register thing.
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We've already talked about that
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it's kind of tricky. I think it's a good example.
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We also have this register_get.
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Now that doesn't really do anything.
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Theoretically, our view model could come up
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with like a list of countries
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and do a bunch of cool stuff to verify that
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it's going to give you drop downs and what not.
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It doesn't do any of that stuff
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So we're not going to test it.
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We also have this index one
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which doesn't really do anything, just verifies the user.
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Now, that would be great, and we can test that.
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But I think the most instructive part will be to test
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this part of our application here.
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Now we have a couple of options.
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Recall, we talked about testing the view model
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that would be this part
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talk to about testing the view method that would be
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directly calling this function.
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And we've also talked about an integration test
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where maybe we fire up the web app
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we issue a request in this URL with a post.
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And it will figure out what parameters
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have to be passed to the method and so on.
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So we're going to start by doing the simple thing
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working with this RegisterViewModel.
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Now, let's get going by creating the section for our tests.
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So, we're going to create a new folder
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for organizing our tests
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as we already talked about, over here.
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I'm going to put it next to our project.
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And in here, again, we're going to do some organizations.
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So I'll have account_tests, plural.
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We're having more than one test.
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Now we could test this with a built in unit test framework
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we could build it, test it with pytest
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we could test it with something like Nose
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or you know, other ones.
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However, in the flask documentation
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all the examples are using pytest.
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So we're going to use pytest as well.
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So, in order to use pytest, we have to install it
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and say that it's a requirement.
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And actually, there's a few things we might want to use.
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So I'm going to come over here.
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And in our development one, this is only for dev
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it's not a production thing.
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I'm going to put 4 libraries, pytest
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pytest-cov, webtest and clarity.
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And then we're going to go down here to the terminal
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and make sure that we pip install those.
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All right, looks like I already have them, that's great.
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So, those are installed for our project and ready for us.
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When we're writing tests with pytest
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what we've got to do is come over here
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and just create a function and has to start with the word
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test_ underscore and be a void method.
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So, we can put whatever what.
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Let's put an example here like this
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and then we could print test test example, like so.
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And then the way you test with pytest is you say assert
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and then you could assert something
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like one plus two equals three.
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Now, how are we going to run it?
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So we come over here and we'll right click
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and we say run, says run pytest in there.
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Now sometimes it won't say that.
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Sometimes it will.
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We run it, looks like it's working great.
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If it doesn't, you can come over here and say Edit
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add Python tests, pytests, and then swipe the script path
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and then script, swipe that.
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Okay, so that's what you could do
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but it looks like it already discovered it for us.
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So here you can see in our example.
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We printed out test example
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and just look at all the results.
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It looks like it passed.
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And you should always verify that if it's not passing
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you're also detecting that.
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So here you go. When I had it wrong, it says it looks like we expected three
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but we got four, not the same.
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Alright, so I'll put this back.
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This is not really our test.
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This is just a super, super simple example to show you
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how to get things set up and running with pytest.
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But I'll go and leave it here
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for since it's a course, I wouldn't leave it in a real lab.
