Building data-driven web apps with Flask and SQLAlchemy Transcripts
Chapter: Testing web apps
Lecture: 3 types of web unit tests
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Now we're going to group our tests
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into three rough categories
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three types of tests that we're going to have
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when we're testing our web application.
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Now recall I did mention this is not a general course
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or chapter on unit testing
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it's specifically focused on testing the web applications.
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So there's probably other types of tests
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but in our world of testing our web app
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these are the three that we're going to focus on
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and I'll touch on a few more just really quickly.
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So at the lowest, simplest level
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let's start there
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we probably want to test our view models.
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Remember view models are central
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to the data exchange with the user
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with the template, with the view
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and a lot of the validation that we have
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the data validation that's in there
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resides hopefully in these view models.
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So what makes testing them special?
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Well remember internally very often
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they implicitly use a request object.
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So somehow we have to provide this view model
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a fake request or a pre-populated request
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with the data that we need it to work with.
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So this is pretty straightforward.
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We'll also see that sometimes
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these view models talk to the database
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that might be a problem.
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Typically we want to test in isolation
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control very carefully what the database would have said
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and then make sure that the view model responds accordingly.
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So we're going to address that as well in these tests.
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Moving up in a richer, testing-more-at-once side of things
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we might want to test the view method.
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This is the actual thing that has the app.route decorator
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or the blueprint.route decorator
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we'd like to call that as if it were a web request
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not through the whole system
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but we'll just call that function.
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It is a function, we can call it.
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But remember this also works with requests
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maybe even with response
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it might also talk to the database.
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It has a bunch of stuff going on working with Flask
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so we're going to need to carefully spec that out
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or provide it something that will work
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in the way that it expects.
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We also might want to create the entire web application
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let the register blueprint, the database init
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all that kind of stuff get up and running
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and then we're going to feed
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to the overall application a particular URL
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make sure that it finds its way to the right view method
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and that it does the right thing.
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So we'll see that with the testing infrastructure from Flask
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we can actually create a fake request
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as if we were actually running the web application
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we're not going to do it
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not really firing up a server
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going to create a test version
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but then we can simulate
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a browser sending requests to it
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and make sure we're getting the right behavior there as well.
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So these are the three core types of tests
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that we're going to focus on in this chapter.
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On the left in terms of even simpler
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we might have algorithmic tests
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and tests working with other parts of our application
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that are not particular to the web framework.
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And on the right we might even go farther
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and actually deploy our web application
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to say a test server
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QA server, something like this
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and then use Selenium to make
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legitimate requests against it
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and even run the JavaScript
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and interact with it that way.
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So there's lots more we could do
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but these are the three that we're going to focus on
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in the unit test world around web applications.
