Tkinter mock UI test example

app.py

import datetime
import traceback

from PyQt5.QtGui import QFontDatabase
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QVBoxLayout, QLabel, QTextEdit

_STATE_LABEL_PREFIX = 'State: '


class WoWHMI(object):
    def __init__(self, command, command_callback=None):
        self.command = command.strip()
        self.command_callback = command_callback

        self.app = QApplication([])
        try:
            self.app.setStyle('Macintosh')
        except Exception:
            self.app.setStyle('Fusion')

        self.window = QWidget()
        self.window.setWindowTitle(
            '{} - {}'.format(self.__class__.__name__, self.command)
        )
        self.window.resize(640, 480)

        self.text_log = QTextEdit()
        self.text_log.setFont(QFontDatabase.systemFont(QFontDatabase.FixedFont))
        self.label_state = QLabel('{}{}'.format(_STATE_LABEL_PREFIX, 'unknown'))

        self.button = QPushButton(self.command)
        self.button.clicked.connect(self.on_click_button)

        self.layout = QVBoxLayout()
        self.layout.addWidget(self.text_log)
        self.layout.addWidget(self.label_state)
        self.layout.addWidget(self.button)

        self.window.setLayout(self.layout)

        self.window.show()

    def on_click_button(self):
        message = self.command.strip().lower()

        log_line = '{} - {} - {}'.format(
            datetime.datetime.now(),
            'sending command',
            repr(message)
        )

        if self.command_callback is not None:
            try:
                log_line += ' - {}'.format(repr(self.command_callback))
                self.command_callback(message)
            except Exception:
                log_line += '\n{}'.format(traceback.format_exc())
        else:
            log_line += ' - callback not given!'

        self.text_log.append(log_line)

    def set_state(self, state):
        self.text_log.append('{} - {} - {}'.format(
            datetime.datetime.now(),
            'received state',
            repr(state)
        ))

        self.label_state.setText('{}{}'.format(_STATE_LABEL_PREFIX, state))

    def run(self):
        self.app.exec_()


if __name__ == '__main__':
    import sys

    command = None

    try:
        command = sys.argv[1]
    except Exception:
        print('error: need to pass in command string as first argument')
        exit(1)


    def command_callback(command):
        print(repr(command))


    app = WoWHMI(
        command,
        command_callback,
    )

    app.run()

app_test.py

import unittest

from PyQt5.QtWidgets import QTextEdit
from hamcrest import assert_that, equal_to
from mock import Mock, call

from hmi.hmi.app import WoWHMI


def command_callback(command):
    pass


class WoWHMITest(unittest.TestCase):
    def setUp(self):
        self.command_callback = Mock(spec=command_callback)

        self.subject = WoWHMI(
            command='some_command',
            command_callback=self.command_callback
        )

    def test_on_click_button(self):
        self.subject.text_log = Mock(spec=QTextEdit)

        self.subject.on_click_button()

        assert_that(
            self.command_callback.mock_calls,
            equal_to([
                call('some_command')
            ])
        )

        assert_that(
            len(self.subject.text_log.append.mock_calls),
            equal_to(1),
        )

    def test_on_click_button_no_command_callback(self):
        self.subject.text_log = Mock(spec=QTextEdit)

        self.subject.command_callback = None

        self.subject.on_click_button()

        assert_that(
            self.command_callback.mock_calls,
            equal_to([])
        )

        assert_that(
            len(self.subject.text_log.append.mock_calls),
            equal_to(1),
        )

    def test_set_state(self):
        self.subject.text_log = Mock(spec=QTextEdit)
        self.subject.label_state = Mock(spec=QTextEdit)

        self.subject.set_state('some state')

        assert_that(
            len(self.subject.text_log.append.mock_calls),
            equal_to(1)
        )

        assert_that(
            self.subject.label_state.setText.mock_calls,
            equal_to([call('State: some state')])
        )