Python Mocking Out Two File Open Contexts

I am trying to write some unit tests using mock for some code that looks like this:

# Write some text to edit to a file
with tempfile.NamedTemporaryFile(delete=False) as tf:
    tfName = tf.name
    tf.write(text_to_edit)

# Edit the text with vim
edit_file(tfName)

# Read edited text
with open(tfName, 'r') as f:
    text = f.read()

# Delete the file
os.remove(tfName)

# ... do stuff with text ...

This was my initial attempt at creating mock objects for that code:

@pytest.fixture
def mock_tempfile(mocker):
    new_tfile_obj = mock.MagicMock()
    tfile_instance = mock.MagicMock()
    tfile_instance.name.return_value = 'mockTemporaryFile'
    mocker.patch('tempfile.NamedTemporaryFile', new_tfile_obj)

    new_open = mock.MagicMock()
    fake_file = mock.MagicMock(spec=file)
    new_open.return_value = fake_file
    new_tfile_obj.return_value = tfile_instance
    mocker.patch('__builtin__.open', new_open)

    return (new_tfile_obj, tfile_instance, new_open, fake_file)
    # ... Code to mock edit_file/modify the temp file are in the actual test ...

However, I don't expect that to be anywhere near what should be used. I'm totally lost on how I would mock something like that.