Building Data-Driven Web Apps with Pyramid and SQLAlchemy Transcripts
Chapter: Testing web apps
Lecture: Getting started with tests
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And see we have a new project pypi_testing.
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Again, this just sort of a save point.
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Let's open that up.
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Now when we created this, we used Cookiecutter.
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We said cookiecutter pyramid starter.
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And it asked a few questions, and boom.
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Out popped a bunch of stuff.
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One of the things we got, was this little test section.
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Now you can see, it's creating some view tests
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based on the built-in unit tests framework.
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We could also use pytest.
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But it's using the built-in one.
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So we are going to use the built-in one as well
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just to be consistent.
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But it really doesn't matter which framework you're using.
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And it's just doing standard things here.
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It's setting up and tearing down a few things.
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And then it's testing one of the views.
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I noticed it's creating this testing.dummy_request.
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Where does that come from?
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Pyramid. So pyramid has built-in testing capabilities
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to do things like give us either a fake request
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or a fake web app that it sort of spins up
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out of its internals.
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And then here we're calling some
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what used to be a view method passing the request
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getting the model back from it.
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Then we can test things like
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hey this model that comes back, does it have a project?
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I think this is maybe project details
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something to that effect.
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Anyway this used to be a valid test.
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So here's how we're going to test.
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Some of it here you can see a more advanced version.
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These are the whole web app.
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We're creating not just a test, a dummy request
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but a test web app
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based on our main method that we're calling
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here from our __init__.
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So these are some of the things you're going to work with.
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But instead of just working with these tests here
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we're going to go and do something better.
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We're going to organize this into things
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that are focused around our controllers
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and grouped in that way.
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Let's go over here and say new package, I guess.
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And we will call this tests.
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And we'll leave this one here for a moment.
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Eventually we'll delete it.
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But for now, lets just leave it as an example.
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And let's focus initially on the account.
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So remember to create different test files
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for the various controllers, I will call it account_test.
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And we're going to get started by importing
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unittest and creating a testcase.
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And the way this works in this framework
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is everything derives from testcase.
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And then it has methods that are test something.
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All of these test_ whatever methods
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will be run by the test framework. Okay.
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So let's suppose we want to test register
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validation, valid. I want to do valid one.
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I want to do another one that'll say no email let's say.
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Let's do this first one here.
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Now I'm going to arrange these tests
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structure them in a way that I think
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is a pretty good pneumonic for folks.
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It's going to use what's called the 3 A's.
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The 3 A's of testing.
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Which is Arrange, Act, then Assert.
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So we're going to do all of our setup.
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Then we're going to do the one thing
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that we're trying to do, in this case validate our data.
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And then we're going to assert that it's valid
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or something to that affect.
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Depending on whatever outcome we're after.
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So what's the arrange?
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Well let's arrange things by creating
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one of these register view models.
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So it's going to be a register view model.
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Now, we could import this like so
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where it goes up at the top. That's fine.
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However, look back over here.
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There's this, or the convention that they're using
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where they're importing the dependencies
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only within the test.
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And the benefit there is that this only runs
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if we run the test.
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It doesn't add any overhead.
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Where would the overhead come from?
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Well, if we look over here
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when we call config scan to go find all the routes
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it's going to look through every file including the tests.
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And we want to isolate them as much as possible.
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So we can do that by taking a step back here
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and say import locally, like that.
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So let's go over here and call this out as a range.
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Great. Now we have to pass something. A request.
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Oh, where do we get that from?
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Well we sort of saw that before.
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So we're going to go import pyramid.testing.
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And we'll get a dummy request.
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There's also sorts of things we can get.
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Dummy session. Dummy rendering factory.
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We want a dummy request.
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And we're going to pass that request here.
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Now one thing that's a little annoying
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remember on all of our view models
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we said this is a request.
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There's not a good enough base class
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that's shared across dummy request
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and real request that describes all the things
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that happen there to make
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make the intellisense and whatnot useful.
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So this is going to complain.
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And we can just say, no no
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this is going to be fine.
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Just don't check this.
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All right, so this arranges everything.
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Now we have to act vm.validate.
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So validate the data.
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And then we have to assert.
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So self.assert is None.
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vm.error. So we want to say, there are
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not is not, is None. There we go.
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We want to say there is no problem with this.
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And the way it's working right now
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it's not going to be so great.
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We're not done arranging.
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We haven't passed any data.
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But let's just run this. See our test fail.
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It says that, you know, here's a string
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that is, you know, is invalid in some sense.
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So let's try that. How do we run our test?
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Well, we can come over here and we can right click
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and we can say run unit test in account.
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Let's do that. We're going to say run.
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We get a nice little test runner over here.
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This one that did nothing
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oh, of course it passed.
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But this one, it failed with some errors.
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Let's see. It said, hm, in fact it just crashed
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trying to do this. Look at that error.
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DBSession.factory execute that line right there.
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find_user_by_email is crashing because that is None.
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And this really highlights one of the challenges
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that we're going to run into.
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We're trying to do this register thing
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and we want to validate it.
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But this is actually going to the database.
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All right, but let's finish our arrange first.
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So in order to simulate submitting the form
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we have to go to the request.
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And we got to go to Post.
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And we have to say this is going to be
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having an email, which is empty
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and a password, wait, this is valid, right.
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Let's put some valid email there.
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The letter a, that's my favorite.
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All right so here's an email.
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Here's a password. This should work.
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Let's run the test again.
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But we're getting this database thing.
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All right, whew, that's annoying.
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We're going to come back and we're going to figure out
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how to fix that.
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But before we do, let's just do one more bit
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of overall organization.
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If we split our test into multiple places here
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like we're going to have
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PackageController tests
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a lot of package tests
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we're going to have tests here
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and we're going to have tests there.
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And we don't want to keep right clicking
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that it run these, no run those.
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We want an ability to just say run them all.
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So let me show you really quick
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a technique we can use for that.
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Another file, _all_tests.
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And what we can do is we can import
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all of the other tests. So we can import
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let's just do * and package_test.
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We can PyCharm no no, let's just leave these alone.
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These are meant to be here.
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I know they look like they do nothing.
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But they do something. And we can go run this.
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It's not going to come out as good as you think.
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So notice it doesn't even have
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the ability to run unit tests.
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'Cause PyCharm doesn't see it.
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So here's a super simple little hack we can do.
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So we can just create this little, effectively
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empty test class. So PyCharm when we click over here says
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oh, running the test there.
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And then it actually runs all tests
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which always always passes.
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But, then we see these others over here like that.
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Yeah. So we'll be able to organize them from this.
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And that way we just add stuff here
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and just keep running the same command.
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And we won't skip or accidentally overlook any of them.
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All right, with that in place
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we're ready to come back and work on this next.
