def test_callback_once():
"""
Test that callbacks attached with the once flag
will only be triggered once and removed afterwards
"""
obj = EventMixin()
data = { "a" : 1 }
expected = { "a" : 2 }
def callback(val, event_origin=None):
data["a"] += val
obj.on("increase", callback, once=True)
obj.trigger("increase", 1)
assert data["a"] == expected["a"]
# at the second time the event triggers, the callback
# is no longer attached, so the value in data.a should
# remain the same
obj.trigger("increase", 1)
assert data["a"] == expected["a"]
def test_callback():
"""
Test adding a callback for an event
"""
obj = EventMixin()
data = { "a" : 1 }
expected = { "a" : 2, "b": 3 }
# the callback will increase the value
# of data.a everytime it is triggered
def callback(val, event_origin=None):
data["a"] += val
# attach callback to event
obj.on("increase", callback)
# trigger event (val=1)
obj.trigger("increase", 1)
assert data["a"] == expected["a"]
# trigger event (val=1)
obj.trigger("increase", 1)
assert data["a"] == expected["b"]
def test_event_origin():
"""
Test that event_origin references is passed
correctly to callbacks
"""
obj = EventMixin()
def callback(event_origin=None):
assert event_origin == obj
obj.on("test", callback)
obj.trigger("test")