Printing to Console in pytest

When using `pytest` for writing and executing tests, directly printing to the console can sometimes be challenging, especially if you want to see those outputs during normal test runs. This article discusses various approaches to effectively print to console when working with `pytest`.

Why Printing in `pytest` Isn't Straightforward

In `pytest`, print statements are captured by default, meaning that they can be suppressed in the final test output. This is done to keep the output clean and readable, primarily focusing on the results of the tests themselves. However, seeing print outputs can be useful, particularly for debugging or logging.

Default Behavior

By default, `pytest` captures output from Python’s `sys.stdout` and `sys.stderr` streams and presents them only when a test fails. This means regular print statements do not appear in the output for passing tests.

Approaches to Print in Pytest

Here are several methods to print to the console when using `pytest`:

1. Using the `-s` Option

Running pytest with the `-s` option disables all output capturing, allowing print statements to display as usual:

• `capsys`: Captures output from `sys.stdout` and `sys.stderr`.
• `capfd`: Captures output at the file descriptor (fd) level.