add

python/pytest-fixtures.md

@@ -8,6 +8,15 @@
 * In generally we call [test fixture](https://en.wikipedia.org/wiki/Test_fixture) the environment in which a test is expected to run.
 * Pytest uses the same word for a more generic concept. All the techniques that make it easy to set up the environment and to tear it down after the tests.
 
+General examples:
+
+* Setting up a database server - then removing it to clean the machine.
+* Maybe filling the database server with some data - emptying the database.
+
+Specific examples:
+
+* If I'd like to test the login mechanism, I need that before the test starts running we'll have a verified account in the system.
+* If I test the 3rd element in a pipeline I need the results of the 2nd pipeline to get started and after the test runs I need to remove all those files.
 
 ## PyTest Fixture setup and teardown xUnit style
 {id: pytest-fixture-setup-teardown}
@@ -16,6 +25,10 @@
 {i: setup_module}
 {i: teardown_module}
 
+{aside}
+There are two mechanism in PyTest to setup and teardown fixtures. One of them is the xUnit-style system that is also available in other languages such as Java and C#.
+{/aside}
+
 ![](examples/pytest/test_fixture.py)
 
 See next slide for the output.