Introduction

pytest is a testing framework for the python programming language. Based on the official documentation - pytest makes it easy to write small tests, yet scales to support complex functional testing for applications and libraries.

In this article, I am going to include some basic features of pytest. As I learn more about the framework, I will continue to add more posts around the same topic.

Pytest can be used in a variety of tests which include frontend, backend, unit testing, etc.

How pytest detects test cases

1. test file starts with test_. Example: test_sum.py
2. test file ends with _test. Example: sum_test.py

• Important thing to note here is, pytest finds file in the current directory as well as subdirectories.

3. test files can have classes or functions.
4. For class, do not include __init__()
5. Functions should also start with test_
6. For class, the name must start with Test and the method name must start with test_.

example:

def test_tc01():
    print("my first test case")

def test_tc02():
    print("my second test case")

Running pytest

pytest <options> testdirectory

• If you are using markers (I will cover this in another post)

pytest -m <marker name>

In the example below, regression is the marker. So in order to run regression, use the following command:

pytest -m regression

example:

@pytest.mark.regression
def test_tc01():
    print("my first test case")

@pytest.mark.regression
def test_tc02():
    print("my second test case")

Fixtures

pytest fixtures are used to perform setup and teardown for the automated test cases. Setup usually is responsible for obtaining test data, preparing DB connections, starting a web browser/driver, etc. On the other hand, tear down is responsible for closing DB connection, closing web browser/driver, updating test results, etc.

example:

@pytest.fixture
def setup_tc():
    print("setup code goes here")

@pytest.mark.regression
def test_tc01():
    print("my first test case")

@pytest.mark.regression
def test_tc02():
    print("my second test case")

In the above example, setup_test is going to be executed before both the methods test_tc01 and test_tc02.

If we want to execute the setup only once for the entire module then we have to use the argument scope.

The possible value of scope are:

1. function
2. class
3. module
4. package
5. session

Reporting

Like most frameworks, pytests provide some options to check the status of the execution. One of the common ways to generate reports is to use pytest-html.

example: pytest --html=my_test_report.html