Python has several types of testing including unit, integration, and system testing. Pytest is a popular framework that supports unittest-style assertion tests, doctest-style example tests, and test discovery from file and method names. Pytest allows parametrizing tests by decorating functions with @pytest.mark.parametrize to test a function with multiple inputs.

1. Python testcase
Authoring

2. Testing Types
 unit testing - test functionality of
individual procedures
 integration testing - test how parts
work together (interfaces)
 system testing - testing the whole
system at a high level (black box,
functional)

3. Testing in Python
 unittest - assertion based
 doctest - example based, integrated with docstrings
 pytest - framework that supports all of the above and more

4. Pytest Test Discovery
 test_*.py or *_test.py files, imported by
their package name.
 Classes prefixed with Test (without an
__init__ method)
 Functions or methods prefixed with test_

5. Examples of valid and
invalid pytest file names
 test_login.py - valid
 login_test.py - valid
 testlogin.py -invalid
 logintest.py -invalid

6. examples of valid and invalid pytest test methods
 def test_file1_method1(): - valid
 def testfile1_method1(): - valid
 def file1_method1(): - invalid

7. Parametrize
When you want to test a number of inputs on the
same function, use @pytest.mark.parametrize.