New Monitor class in pytddmon

# coding: utf-8
import unittest

class Monitor:
    def __init__(self, file_finder, get_file_size, get_file_modtime):
        self.file_finder = file_finder
        self.get_file_size = get_file_size
        self.get_file_modtime = get_file_modtime

        self.snapshot = self.get_snapshot()

    def get_snapshot(self):
        snapshot = {}
        for file in self.file_finder():
            file_size = self.get_file_size(file)
            file_modtime = self.get_file_modtime(file)
            snapshot[file] = (file_size, file_modtime)
        return snapshot

    def look_for_changes(self):
        print "\nused to be: " + str(self.snapshot)
        new_snapshot = self.get_snapshot()
        change_detected = new_snapshot != self.snapshot
        self.snapshot = new_snapshot
        print "now is: " + str(new_snapshot)
        return change_detected

class test_change_detection(unittest.TestCase):

    def test_modification_time_changed(self):
        def file_finder():
            return ['file']
        def get_file_size(file):
            return 1
        modtime = [1]
        def get_file_modification_time(file):
            return modtime[0]
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        modtime[0] = 2
        change_detected = monitor.look_for_changes()
        assert change_detected

    def test_nothing_changed(self):
        def file_finder():
            return ['file']
        def get_file_size(file):
            return 1
        def get_file_modification_time(file):
            return 1
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        change_detected = monitor.look_for_changes()
        assert not change_detected

    def test_adding_file(self):
        files = ['file']
        def file_finder():
            return files
        def get_file_size(file):
            return 1
        def get_file_modification_time(file):
            return 1
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        files.append('file2')
        change_detected = monitor.look_for_changes()
        assert change_detected

    def test_renaming_file(self):
        files = ['file']
        def file_finder():
            return files
        def get_file_size(file):
            return 1
        def get_file_modification_time(file):
            return 1
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        files[0] = 'renamed'
        change_detected = monitor.look_for_changes()
        assert change_detected

    def test_change_is_only_detected_once(self):
        files = ['file']
        def file_finder():
            return files
        def get_file_size(file):
            return 1
        def get_file_modification_time(file):
            return 1
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        files[0] = 'changed'
        change_detected = monitor.look_for_changes()
        change_detected = monitor.look_for_changes()
        assert not change_detected

    def test_file_size_changed(self):
        files = ['file']
        filesize = [1]
        def file_finder():
            return files
        def get_file_size(file):
            return filesize[0]
        def get_file_modification_time(file):
            return 1
        monitor = Monitor(file_finder, get_file_size, get_file_modification_time)
        filesize[0] = 5
        change_detected = monitor.look_for_changes()
        assert change_detected

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