Python Unit Test Automation

Listing 5-9.  test_module08.py
import pytest
@pytest.fixture()
def fixture01(request):
    print("\nIn fixture...")
    print("Fixture Scope: " + str(request.scope))
    print("Function Name: " + str(request.function.__name__))
    print("Class Name: " + str(request.cls))
    print("Module Name: " + str(request.module.__name__))
    print("File Path: " + str(request.fspath))
@pytest.mark.usefixtures('fixture01')
def test_case01():
    print("\nI'm the test_case01")
The following is the output of Listing 
5-9
:
============================ test session starts =======================
platform linux -- Python 3.4.2, pytest-3.0.4, py-1.4.31, pluggy-0.4.0 --  
/usr/bin/python3
cachedir: .cache
rootdir: /home/pi/book/code/chapter05/test, inifile:
collected 1 items
test_module08.py::test_case01
In fixture...
Fixture Scope: function
Function Name: test_case01
Class Name: None
Module Name: test.test_module08
File Path: /home/pi/book/code/chapter05/test/test_module08.py
I'm the test_case01
PASSED
========================= 1 passed in 0.06 seconds =====================
Scope of pytest Fixtures
pytest provides you with a set of scope variables to define exactly when you want to use 
the fixture. The default scope of any fixture is the function level. It means that, by default, 
the fixtures are at the level of function.

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Chapter 5 
■
 pytest
97
The following is the list of scopes for pytest fixtures:
•  function: Runs once per test
•  class: Runs once per class of tests
•  module: Runs once per module
•  session: Runs once per session
To use these, define them like this:
@pytest.fixture(scope="class")
•  Use the function scope if you want the fixture to run after every 
single test. This is fine for smaller fixtures.
•  Use the class scope if you want the fixture to run in each class of 
tests. Typically, you’ll group tests that are alike in a class, so this 
may be a good idea, depending on how you structure things.
•  Use the module scope if you want the fixture to run at the start of 
the current file and then after the file has finished its tests. This 
can be good if you have a fixture that accesses the database and 
you set up the database at the beginning of the module and then 
the finalizer closes the connection.
•  Use the session scope if you want to run the fixture at the first test 
and run the finalizer after the last test has run.
There is no scope for packages in pytest. However, you can cleverly use the session 
scope as a package-level scope by making sure that only a specific test package runs in a 
single session.
pytest.raises()
In unittest, you have assertRaises() to check if any test raises an exception. There 
is a similar method in pytest. It is implemented as pytest.raises() and is useful for 
automating negative test scenarios.
Consider the code shown in Listing 
5-10
.