How to change the default rootdir ($PWD) to some other path

Is it possible to change the default rootdir (where tests and conftest.py are located) based on a file in the current working directory?

I am using pytest for testing a C project (not Python), so it is quite common to have a separate source and build directory. Additionally, tests are located in a subdirectory. The directory layout could be:

$srcdir/test/conftest.py    (contains pytest_addoption and other stuff)
$srcdir/test/pytest.ini     (contains python_files to override the test file pattern)
$srcdir/test/some_tests.py

Right now, tests are executed from the build (or source) directory by passing the test directory, e.g.:

srcdir$ pytest test
objdir$ pytest $srcdir/test

What I am trying to achieve is being able to run the same tests with:

srcdir$ pytest
objdir$ pytest

To this effect, I have tried to create $srcdir/pytest.ini and $objdir/pytest.ini containing testpaths = test and testpaths = $srcdir/test respectively. Unfortunately $srcdir/test/conftest.py is initially not picked up and pytest_addoption is not executed.

Essentially I want to redirect the rootdir by creating a file in the current working directory (source or build dir). Is this possible? What alternatives do I have, while trying to keep the number of pytest-related files (e.g. conftest.py) in the top-level directory to a minimum?

[nicoddemus]

Let me try to quickly summarize:

• sys.path: pytest won’t look into that at all, it is used by the Python runtime to find modules during import
• rootdir: is determined after finding a suitable config file (pytest.ini) or by the common-ancestor of all paths given in the command line (the logic is explained in detail here).

Test files are always searched starting from paths given in the command-line. If if no path is given in the command-line, testpaths is used, otherwise then $PWD is used.

[Zac-HD]

@nnop - we have a general policy of closing question-issues after two weeks of inactivity, which makes it easier for users and contributors to sort through all the other issues (e.g. bug reports and feature requests) we get.

Glad @nicoddemus could help out though!