Effective PyCharm Transcripts
Chapter: Unit testing
Lecture: Running pytest tests
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Now that you've seen the app and have some idea of the library that we're going
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to test. It's time to actually get things set up for running unit tests.
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See the test runner, make sure we have our requirements set up correctly for that
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as well. There's a couple of things we can do that will make working with
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the test runner as well as PyCharm a little bit better around the specific naming So what I'm going to do is create a folder or we're gonna put our
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test and I'm going to name it. Test plural when we do that, we can come over here and right click and say run 'pytest' in tests.
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If I were to click on app, I don't get any run if I click on a file, I just get run that file.
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But because it's called tests, PyCharm knows that it's going to look here for running the tests Now, how does it,
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know 'pytest', There's other types of testing framework, including the built in unit tests. But let's go check that out really quick.
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If we go down here to tools Python integrated tools, you can set up the default test runner and notice it can auto detect it can
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be 'pytest' 'nosetest' 'twisted trial' or the built in unit tests. I recommend as long as you don't mind having external dependencies using py test.
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If you want to avoid dependencies, use unit test, 'pytesters' a decent option because even if things are built with unit tests
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you can still run them by running 'py test' against it. Okay, So that's why we saw pytest and not some other test framework run
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right click and around there for this to work. Of course we're going to have to have pytest in our requirements and make sure
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that we have. pytest installed, luckily we already do. But if for some reason you don't make sure that you've
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installed pytest does not come with Python, but it is clearly the most popular way to write tests in Python. We'll go down here. If we ran run test,
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it wouldn't do anything. So let's go and add some files again. Naming matters here. So this is going to be table tests. I would love to say tests,
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url because this file chances are is going to more than one test. Let's go ahead and try that and just see what happens.
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So we can come down here in the way we write a pytest test is we just write the name. So the first test that we're gonna write is test
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hello_pytest( ) or something like that. In in here we can just assert one is greater than zero or something. This is how you write tests or pytest.
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It has the name. test_ and the method here other than that you can
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name it whatever descriptive thing you want and then you just assert things and pytest hooks into the assert infrastructure here and runs a test.
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So let's go and try to run our tests, sadly no tests found what's going on here. Well, I wanted to show you that because I'm sure at some point you run
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into it. The problem is that these have to be named test singular, even though they contain multiple tests, All right, try it again. There we go.
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So our test is running down here. You see, we got the test. Hello pytest Past 100%. Perfect. If we wanted to see what it looks like if it failed,
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we could change our assert to something that's false and you can see it's said over here this this is not true. Right So that's the problem.
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There's a lot of other interesting things we can test with pytest, but that's a start right now.
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If we come down here notice we've got this cool test runner. It says okay, these are all the test results. Here's the table tests. Hello pytest.
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Let me actually rename this one to. 'hello_test'. All right. Again. That way we can have our table tests as well and we'll see multiple
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things going on down here to this test. Runner is really fantastic notice when we first right,
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click here and said run pytest in tests that created a run configuration up there
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and now I can just hit command R or rather or just press this button like we have been. Additionally, you can run down here and that means the same
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thing. But we can hide, let's have a failing test. We run this now. You can see we can hide just the hide the passing tests and just show the
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failing tests right now. One thing that's really cool about this is we can not just run the test, but if we've got a bunch we can run just the
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failed ones. So maybe you've got 1000 tests and there's just one that's failing. You're trying to fix it. Do you really want to wait for all 999 of
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the other ones to run to tell you if the progress you're making on the one test works. No switch to this now if you hit CTRL+R we can reset
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it over there. But if you press this and you just say rerun the failed ones. Rerunning this will just keep running the failed one.
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So a full project rerun is what you need. We can sort alphabetically, we can sort by duration.
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Notice these are fast but if it took a little while it will show you how long it takes. You can expand collapse and so on.
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Let's go rerun it to get our other non failing run back. Beautiful, beautiful. One other thing that is quite interesting here is this we can
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actually toggle the test to run all the time. We'll see that later. But yeah, this test runner down here is really fantastic.
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We're going to be using it while we're working on these various tests.