Building data-driven web apps with Flask and SQLAlchemy Transcripts
Chapter: Testing web apps
Lecture: Why write tests (web)
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Our web app is basically built.
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All we have left to do is test and deploy it.
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So let's talk about testing web applications.
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Now this is not a chapter on unit testing
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and all of it's benefits in general.
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The goal is to focus on testing web applications.
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Addressing some of the challenges that we'll see
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that can be hard of working with web apps
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in terms of testing.
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For example, how do we like set up the web framework
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around it if it depends upon things like request object.
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And what are some of the techniques we can use
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to take advantage of stuff the web app already provides us
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like the URL structure and so on.
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Let's begin by asking the question, why test?
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Why should we write tests at all?
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Well, your first response is probably
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So that we can find our bugs.
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There surely are bugs in our web app.
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Let's make sure we find them and then get rid of them.
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And that is great.
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That's not the only reason to write tests.
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These days in modern software development
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we have a lot of infrastructure in place to help
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with things like continuous deployment
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and checking code and verifying that we don't step
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on each others feet if we're working on a team.
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Things like that.
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And testing for Python web apps is really one
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of the few verifications that we have that we can work with.
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Let's suppose that we have continuous integration
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which is a system like TeamCity or Travis CI
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that looks at our GitHub repository.
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Watches a branch or watches for PR's.
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And when a change comes in
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it will automatically check it out and build our project.
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And that build probably includes running tests.
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But if we don't have tests
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that build passing, what does that mean?
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I actually don't know what it means, in term of Python.
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Maybe we could install the dependencies
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register the website.
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That might be about it.
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Because Python doesn't even have compiling.
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So this testing in place means
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that when our automatic builds pass
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that actually says something about the state of our web app.
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If we're going to go farther, and go with continuous delivery
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and automatically deploy our site
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when we put it onto a branch in the build passes
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when we really need some sort of verification
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with our tests.
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So these tests are important foundational items
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for so many things that we might do
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around our project.
