mock_open

unittest.mock

function (source)

mock_open(mock=None, read_data='')

A helper function to create a mock to replace the use of `open`. It works
for `open` called directly or used as a context manager.

The `mock` argument is the mock object to configure. If `None` (the
default) then a `MagicMock` will be created for you, with the API limited
to methods or attributes available on standard file handles.

`read_data` is a string for the `read`, `readline` and `readlines` of the
file handle to return.  This is an empty string by default.

© Python Software Foundation. PSF License Version 2 · Official docs ↗

Changed in 3.4, 3.5, 3.8

3.4: Added readline() and readlines() support. The mock of read() changed to consume read_data rather than returning it on each call.
3.5: read_data is now reset on each call to the mock.
3.8: Added __iter__() to implementation so that iteration (such as in for loops) correctly consumes read_data.