Run only specific tests in verbose mode using pytest

Are you tired of running all your tests every time you make a change to your code? Do you want to focus on a specific subset of tests to debug and refine? Look no further! In this article, we’ll explore how to run only specific tests in verbose mode using pytest, saving you time and effort in your testing workflow.

What is pytest and verbose mode?

pytest is a popular testing framework for Python that provides a lot of flexibility and customization options. One of the key features of pytest is the ability to run tests in verbose mode, which provides detailed output about the testing process.

Verbose mode can be enabled by using the -v or --verbose flag when running pytest. This flag tells pytest to display more information about the testing process, including the names of the tests being run, the time taken to run each test, and any errors or failures that occur.

pytest -v

Running specific tests in verbose mode

Now that we’ve covered the basics of pytest and verbose mode, let’s dive into the main topic of this article: running only specific tests in verbose mode. There are several ways to do this, and we’ll explore each method in detail.

Method 1: Using the -k flag

The first method is to use the -k flag, which allows you to specify a pattern to match against the names of the tests. This flag is often used in combination with the -v flag to run specific tests in verbose mode.

pytest -v -k "test_specific_test"

In this example, pytest will only run tests whose names contain the string “test_specific_test”. You can adjust the pattern to match the specific tests you want to run.

Method 2: Using the -m flag

The second method is to use the -m flag, which allows you to specify a marker to match against the tests. Markers are a way to categorize tests in pytest, and can be used to run specific tests based on certain criteria.

pytest -v -m "slow"

In this example, pytest will only run tests that are marked with the “slow” marker. You can define your own markers in your tests using the @pytest.mark decorator.

Method 3: Using the --testmon flag

The third method is to use the --testmon flag, which allows you to specify a test monitor script to run. Test monitors are scripts that can be used to filter or modify the tests that are run.

pytest -v --testmon=my_test_monitor.py

In this example, pytest will run the tests using the my_test_monitor.py script. This script can be used to filter out specific tests or modify the testing process.

Examples and use cases

In this section, we’ll explore some examples and use cases for running specific tests in verbose mode using pytest.

Example 1: Running a single test

Let’s say you have a test file called test_example.py with several tests, and you want to run only one of them in verbose mode.

# test_example.py
def test_example1():
    assert True

def test_example2():
    assert False

def test_example3():
    assert True

You can use the -k flag to run only the test_example2 test:

pytest -v -k "test_example2"

This will run only the test_example2 test in verbose mode, displaying the detailed output.

Example 2: Running tests with a specific marker

Let’s say you have several tests with different markers, such as “slow” or “fast”. You can use the -m flag to run only the tests with a specific marker.

# test_example.py
@pytest.mark.slow
def test_slow_test():
    assert True

@pytest.mark.fast
def test_fast_test():
    assert True

You can use the -m flag to run only the tests with the “slow” marker:

pytest -v -m "slow"

This will run only the tests with the “slow” marker in verbose mode, displaying the detailed output.

Best practices and tips

In this section, we’ll cover some best practices and tips for running specific tests in verbose mode using pytest.

Tip 1: Use descriptive test names

When running specific tests in verbose mode, it’s essential to have descriptive test names that accurately reflect the functionality being tested. This makes it easier to identify the tests you want to run and makes the output more readable.

Tip 2: Use markers to categorize tests

Markers are a powerful way to categorize tests in pytest, and can be used to run specific tests based on certain criteria. By using markers, you can easily run tests that belong to a specific category or group.

Tip 3: Use the -v flag judiciously

The -v flag can produce a lot of output, which can be overwhelming if you’re running a large number of tests. Use the -v flag judiciously, and only when you need to debug or refine a specific set of tests.

Conclusion

In conclusion, running specific tests in verbose mode using pytest is a powerful technique that can save you time and effort in your testing workflow. By using the -k, -m, and --testmon flags, you can focus on a specific subset of tests and debug or refine them with ease. Remember to use descriptive test names, categorize your tests using markers, and use the -v flag judiciously to get the most out of this technique.

Flag	Description
-k	Specify a pattern to match against the names of the tests
-m	Specify a marker to match against the tests
--testmon	Specify a test monitor script to run

By following the instructions and examples in this article, you’ll be able to run specific tests in verbose mode using pytest and take your testing workflow to the next level.

• Run specific tests using the -k flag
• Run tests with specific markers using the -m flag
• Use test monitors to filter or modify the tests that are run
• Use descriptive test names and markers to categorize your tests
• Use the -v flag judiciously to debug or refine specific tests

Happy testing!

Frequently Asked Question

Pytest is a powerful testing framework for Python, but sometimes you only want to run specific tests in verbose mode. Here are some frequently asked questions about how to do just that!