How to position test fixture data correctly?

[njlr]

I have a test like so:

py_pytest_main(
  name = "__test__",
)

py_test(
  name = "test_foo",
  main = ":__test__.py",
  srcs = [
    ":__test__",
    "tests/__init__.py",
    "tests/fixtures.py",
    "test_foo.py",
  ],
  data = glob([
    "tests/fixtures/**/*.json",
    "tests/fixtures/**/*.txt",
  ]),
  python_version = "3.10.6",
  package_collisions = "error",
  deps = [
    requirement("pytest"),
    ":foo",
  ],
)

The problem is that my test code loads fixtures like this:

with open('tests/fixtures/example.txt', 'r') as f:
    f.read()

This path works when you are executing in the package directory, but it doesn't work under bazel test

I do not want to modify my Python code because it must work with other tooling

How can I configure Bazel to find the test fixtures?