pytest Quick Start Guide

Capture methods with --capture

Pytest has two methods to capture output. Which method is used can be chosen with the --capture command-line flag:

• --capture=fd: captures output at the file-descriptor level, which means that all output written to the file descriptors, 1 (stdout) and 2 (stderr), is captured. This will capture output even from C extensions and is the default.
• --capture=sys: captures output written directly to sys.stdout and sys.stderr at the Python level, without trying to capture system-level file descriptors.

Usually, you don't need to change this, but in a few corner cases, depending on what your code is doing, changing the capture method might be useful.

For completeness, there's also --capture=no, which is the same as ...