Terminal reporter doesn't print

# test_a.py
def test_foo(request):
    reporter = request.config.pluginmanager.getplugin("terminalreporter")
    reporter.ensure_newline()
    reporter.write("magic", flush=True)

If you run the above file through pytest nothing is written on the output.

$ pytest . 

platform linux -- Python 3.9.6, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: /tmp/workdir
plugins: print-0.3.0
collected 1 item

test_a.py .   [100%]

Though I'd expect something like:

$ pytest . 

platform linux -- Python 3.9.6, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: /tmp/workdir
plugins: print-0.3.0
collected 1 item

test_a.py
   magic .
   [100%]

Note if you remove the flush we do get the message printed, but without respecting the ensure newline (instead you get test_a.py magic.).

Start by running the test_a.py example with pytest and compare reporter.write behavior with and without flush=True. Inspect the terminalreporter entry points used by request.config.pluginmanager, including ensure_newline() and write(). Done means flushed output preserves the requested newline and displays “magic” in the expected position.