test_writetosignal.py

# Mantid Repository : https://github.com/mantidproject/mantid
#
# Copyright &copy; 2017 ISIS Rutherford Appleton Laboratory UKRI,
#     NScD Oak Ridge National Laboratory, European Spallation Source
#     & Institut Laue - Langevin
# SPDX - License - Identifier: GPL - 3.0 +
#  This file is part of the mantid workbench.
#
#
from __future__ import (absolute_import)

import unittest

import sys
from mock import patch
from qtpy.QtCore import QCoreApplication, QObject

from mantidqt.utils.qt.test import GuiTest
from mantidqt.utils.writetosignal import WriteToSignal


class Receiver(QObject):
    captured_txt = None

    def capture_text(self, txt):
        self.captured_txt = txt


class WriteToSignalTest(GuiTest):

    def test_connected_receiver_receives_text(self):
        with patch("sys.stdout.fileno") as mock_fileno:
            recv = Receiver()
            writer = WriteToSignal(sys.stdout)
            writer.sig_write_received.connect(recv.capture_text)
            txt = "I expect to see this"
            writer.write(txt)
            QCoreApplication.processEvents()
            self.assertEqual(txt, recv.captured_txt)
            mock_fileno.assert_called_once_with()


if __name__ == "__main__":
    unittest.main()