Stdin is not a terminal

Hi!
I am trying to test my prompt using pytest and the fixture from the documentation:

@pytest.fixture(autouse=True, scope="function")
def mock_input():
    pipe_input = create_pipe_input()
    try:
        with create_app_session(input=pipe_input, output=DummyOutput()):
            yield pipe_input
    finally:
        pipe_input.close()


def test_gimme_setup(mock_input):
    function_to_test("test")
    mock_input.send_text("user.test\n")
    mock_input.send_text("yes\n")
    assert is_config("test")

When I run the test I get :

ERROR test_aws.py - io.UnsupportedOperation: Stdin is not a terminal.

I am using a mac with Zsh or Bash terminals.

Start with the documented pytest fixture using create_pipe_input(), create_app_session(), and DummyOutput(), then reproduce the Stdin is not a terminal error. Trace which fixture or application entry point accesses stdin and confirm the test can send both inputs without raising the error.