Building data-driven web apps with Pyramid and SQLAlchemy Transcripts
Chapter: Testing web apps
Lecture: Special challenges of the web
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Let's focus on some of the special
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challenges we might have in testing web projects.
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Here is a POST view method that's going to handle
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the postback, when we're doing registration.
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So, this is how users actually register on our site.
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And, you look at it, you can see there's things
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we might want to test, this interaction with the ViewModel
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this error handling, the actual creation of the account.
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But, look carefully. You'll see there are certain areas
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where this is much harder than
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just some sort of algorithmic thing.
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We're creating a register ViewModel
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and, oh it takes a request.
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That's an actual Pyramid request.
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With various dictionaries like the Post, Get, matchdict
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headers, URLs, all sorts of stuff.
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Hmmm, how do we create one of those?
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That could be tricky. Validate.
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Remember the register ViewModel actually goes back
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to the database to make sure the user that's trying
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to register isn't already registered.
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How do we talk to the database?
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We don't actually want to go to the database in our test.
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What we want to do is run these tests in isolation.
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So, how do we make that still do something meaningful
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without actually going to the database.
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That's really tricky. We're going to create an account.
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Well that's definitely going to go to the database, right.
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Maybe it's also going to send like a welcome email
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who knows what that user service thing does.
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It might do all kinds of things we don't want to happen.
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So, we don't want an email to get sent to a random person
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every time these automatic tests run, right.
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We want to make sure that doesn't happen
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but we might want to verify that the email would
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have been sent correctly.
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Similarly login, what does that mean?
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This redirect that probably throws an exception
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but in a positive way, right, throws a HTTPFound exception
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for /account. So, all of these things are special challenges
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of working with the web when we're doing testing.
