Getting started with pytest Transcripts
Chapter: Welcome to the course
Lecture: Topics covered
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Let's talk about everything we're gonna cover in the course. First off we're gonna talk about test functions.
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They're simple but powerful and we need to know some of the features of pytests that
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helped make test functions so powerful and then we'll talk about test fixtures, parameterization, markers, plugins in configuration.
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But really what are these things? Let's jump in quickly to kind of cover what these things are before we go too
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much further. Test functions like shown here a simple test function that starts with test underscore and uses an assert around this.
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We'll talk about test discovery, How does pytest find these things? We've said that pytest uses the built in python assert.
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We'll look at these enhanced trace backs. Normally you fail a test with a certain and or pass a test with a passing
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assert statement. But we can also use pytest fail and other exceptions, we'll take a quick look at those and sometimes we have code under tests that we
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want to throw an exception in certain cases and we can test for that too.
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We'll also briefly look at test classes because there are sometimes great reasons to run test
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classes after that. We'll jump into fixtures what a fixture is is kind of like set up and tear down So unit test has set up and tear down methods but
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pytest, you can use those but normally we use fixtures and in this case we're showing a dB fixture that database that has some set up the yield,
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sends the database connection to the test and then the rest of it just hangs out until the test is done and then the tear down happens.
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So we'll talk about set up and tear down and returning data. You can also use multiple fixtures protest and even fixtures can use fixtures.
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Pytest comes with some built in fixtures that are pretty powerful and we'll take a
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look at some of those. You can also scope fixture so what scoping means is a fixture can use run the setup and tear down phase after each test or it
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can do it once per module or once per session and a whole bunch of other options. You can also share fixtures between tests and between test files.
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If you throw the fixtures into a conftest.py file so we'll play with that parameterization is super powerful.
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It's a way to write one test that covers many test cases in this example I'm
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having this test finished test function that runs the test cases of a beginning starting state
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starting in to do or in progress or done and then running the same test This is taking the place of three different tests all in one.
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It's pretty cool. So we can talk about in this case parameters, tests will cover that but you can also parameters fixtures,
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it's a little bit different syntax but we will cover that of course and using multiple
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parameters can make it very powerful to use multiple parameters per row or you can stack these parameterizations so that you have a test
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matrix. Markers are pretty powerful. So we'll cover those in this example. We are using the mark skip marker that will tell pytest to not run
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a test. There's some reasons to use that, especially with skip if it's very powerful.
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There's also X fail that will cover and you can use custom workers and those help
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for selecting subsets of tests. You can also combine them and use markers plus fixtures And we'll definitely cover that because it's super powerful.
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Next is plugins plugins are a way to extend pytest functionality and there's
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some amazing third party plugins will cover x test is one that you can allows you to run tests and parallel to speed up testing.
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And we'll also use 'cov' to collect test coverage. These are just too though there are hundreds of plugins available and there you can
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even write your own. We will also talk about configuration because that's one of the
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kind of a neat things about pytest is the configuration options You should have a
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config file and we'll discuss why you need a config file but we'll also the config file could be a pytest any or Pyproject.toml, and we're going
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to use pytest in this course and we'll also look at some cool command line flags. So one of the config options.
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I'm showing is ad ops and that is a way to add flags to run every time, and there's good reasons to use some of them all the time,
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and then other settings, like shown here as test paths and markers.