Files
MyUtils/tests/test_observable.py

608 lines
16 KiB
Python

import pytest
from myutils.observable import NotObservableError, make_observable, bind, collect_return_values, unbind, unbind_all, \
has_listeners, get_listener_count
# Test fixtures
class Data:
def __init__(self):
self.value: str = "initial"
self.number: int = 1
def get_double(self):
return self.number * 2
@pytest.fixture
def data():
return Data()
@pytest.fixture
def observable_data(data):
return make_observable(data)
# Tests
def test_i_can_make_an_object_observable(observable_data):
assert hasattr(observable_data, '_listeners')
assert isinstance(observable_data._listeners, dict)
assert observable_data is observable_data
def test_i_can_bind_a_callback_to_an_attribute():
data = Data()
make_observable(data)
callback = lambda old, new: None
bind(data, 'number', callback)
assert 'number' in data._listeners
assert callback in data._listeners['number']
def test_i_can_receive_notification_when_attribute_changes():
data = Data()
make_observable(data)
called = []
bind(data, 'number', lambda old, new: called.append(True))
data.number = 5
assert len(called) == 1
def test_i_can_receive_old_and_new_values_in_callback():
data = Data()
make_observable(data)
values = []
bind(data, 'number', lambda old, new: values.append((old, new)))
data.number = 5
data.number = 10
assert values == [(1, 5), (5, 10)]
def test_i_can_bind_multiple_callbacks_to_same_attribute():
data = Data()
make_observable(data)
calls1 = []
calls2 = []
bind(data, 'number', lambda old, new: calls1.append(new))
bind(data, 'number', lambda old, new: calls2.append(new))
data.number = 5
assert calls1 == [5]
assert calls2 == [5]
def test_i_can_bind_callbacks_to_different_attributes():
data = Data()
make_observable(data)
number_calls = []
name_calls = []
bind(data, 'number', lambda old, new: number_calls.append(new))
bind(data, 'name', lambda old, new: name_calls.append(new))
data.number = 5
data.name = "test"
assert number_calls == [5]
assert name_calls == ["test"]
def test_i_can_modify_non_observed_attributes_without_notification():
data = Data()
make_observable(data)
called = []
bind(data, 'number', lambda old, new: called.append(True))
data.other_attr = "value"
assert len(called) == 0
assert data.other_attr == "value"
def test_i_can_have_multiple_instances_with_independent_observers():
data1 = Data()
data2 = Data()
make_observable(data1)
calls1 = []
bind(data1, 'number', lambda old, new: calls1.append(new))
data1.number = 5
data2.number = 10
# Only data1 should trigger callback
assert calls1 == [5]
assert data1.number == 5
assert data2.number == 10
def test_i_can_call_make_observable_multiple_times_safely():
data = Data()
result1 = make_observable(data)
result2 = make_observable(data)
assert result1 is result2
assert hasattr(data, '_listeners')
# Should still work normally
called = []
bind(data, 'number', lambda old, new: called.append(new))
data.number = 5
assert len(called) == 1
def test_i_cannot_bind_before_making_observable():
data = Data()
with pytest.raises(NotObservableError) as exc_info:
bind(data, 'number', lambda old, new: None)
assert "must be made observable" in str(exc_info.value).lower()
def test_i_can_set_attribute_that_does_not_exist_yet():
data = Data()
make_observable(data)
values = []
bind(data, 'new_attr', lambda old, new: values.append((old, new)))
data.new_attr = "first_value"
assert values == [(None, "first_value")]
assert data.new_attr == "first_value"
def test_i_can_preserve_original_class_behavior():
data = Data()
make_observable(data)
# Test that original methods still work
assert data.get_double() == 2
data.number = 5
assert data.get_double() == 10
# Test that isinstance still works
assert isinstance(data, Data)
def test_i_can_collect_the_updates():
data = Data()
make_observable(data)
bind(data, 'number', lambda old, new: new)
bind(data, 'number', lambda old, new: new * 2)
data.number = 5
assert collect_return_values(data) == [5, 10]
# another time to make sure there is no side effect
data.number = 10
assert collect_return_values(data) == [10, 20]
def test_i_cannot_collect_updates_before_making_observable():
data = Data()
with pytest.raises(NotObservableError) as exc_info:
collect_return_values(data)
assert "must be made observable" in str(exc_info.value).lower()
def test_i_can_collect_none():
data = Data()
make_observable(data)
bind(data, 'number', lambda old, new: None)
data.number = 5
assert collect_return_values(data) == [None]
def test_i_can_unbind_a_callback(observable_data):
"""
Unbinding a callback should prevent it from being called.
"""
results = []
def callback(old, new):
results.append((old, new))
bind(observable_data, "value", callback)
observable_data.value = "first"
assert len(results) == 1
unbind(observable_data, "value", callback)
observable_data.value = "second"
assert len(results) == 1 # Should not have increased
def test_i_can_unbind_one_callback_without_affecting_others(observable_data):
"""
Unbinding one callback should not affect other callbacks on the same attribute.
"""
results1 = []
results2 = []
def callback1(old, new):
results1.append((old, new))
def callback2(old, new):
results2.append((old, new))
bind(observable_data, "value", callback1)
bind(observable_data, "value", callback2)
observable_data.value = "first"
assert len(results1) == 1
assert len(results2) == 1
unbind(observable_data, "value", callback1)
observable_data.value = "second"
assert len(results1) == 1 # Should not have increased
assert len(results2) == 2 # Should have increased
def test_i_can_unbind_callback_from_one_attr_without_affecting_others(observable_data):
"""
Unbinding a callback from one attribute should not affect callbacks on other attributes.
"""
value_results = []
number_results = []
def value_callback(old, new):
value_results.append((old, new))
def number_callback(old, new):
number_results.append((old, new))
bind(observable_data, "value", value_callback)
bind(observable_data, "number", number_callback)
observable_data.value = "first"
observable_data.number = 1
assert len(value_results) == 1
assert len(number_results) == 1
unbind(observable_data, "value", value_callback)
observable_data.value = "second"
observable_data.number = 2
assert len(value_results) == 1 # Should not have increased
assert len(number_results) == 2 # Should have increased
def test_unbind_with_non_existent_callback_does_not_raise(observable_data):
"""
Unbinding a callback that was never bound should fail silently.
"""
def callback(old, new):
pass
# Should not raise an exception
unbind(observable_data, "value", callback)
def test_unbind_with_non_existent_attribute_does_not_raise(observable_data):
"""
Unbinding from an attribute that has no listeners should fail silently.
"""
def callback(old, new):
pass
# Should not raise an exception
unbind(observable_data, "non_existent", callback)
def test_i_cannot_unbind_from_non_observable_object(data):
"""
Trying to unbind from a non-observable object should raise NotObservableError.
"""
def callback(old, new):
pass
with pytest.raises(NotObservableError, match="must be made observable"):
unbind(data, "value", callback)
def test_unbind_same_callback_multiple_times_is_safe(observable_data):
"""
Unbinding the same callback multiple times should be safe.
"""
def callback(old, new):
pass
bind(observable_data, "value", callback)
unbind(observable_data, "value", callback)
unbind(observable_data, "value", callback) # Should not raise
unbind(observable_data, "value", callback) # Should not raise
# ============================================================================
# unbind_all() tests
# ============================================================================
def test_i_can_unbind_all_callbacks_from_one_attribute(observable_data):
"""
unbind_all() with an attribute should remove all callbacks from that attribute.
"""
results1 = []
results2 = []
def callback1(old, new):
results1.append((old, new))
def callback2(old, new):
results2.append((old, new))
bind(observable_data, "value", callback1)
bind(observable_data, "value", callback2)
observable_data.value = "first"
assert len(results1) == 1
assert len(results2) == 1
unbind_all(observable_data, "value")
observable_data.value = "second"
assert len(results1) == 1 # Should not have increased
assert len(results2) == 1 # Should not have increased
def test_unbind_all_on_one_attr_does_not_affect_others(observable_data):
"""
unbind_all() on one attribute should not affect listeners on other attributes.
"""
value_results = []
count_results = []
def value_callback(old, new):
value_results.append((old, new))
def count_callback(old, new):
count_results.append((old, new))
bind(observable_data, "value", value_callback)
bind(observable_data, "count", count_callback)
unbind_all(observable_data, "value")
observable_data.value = "first"
observable_data.count = 1
assert len(value_results) == 0 # Should not have increased
assert len(count_results) == 1 # Should have increased
def test_i_can_unbind_all_callbacks_from_all_attributes(observable_data):
"""
unbind_all() without an attribute should remove all callbacks from all attributes.
"""
value_results = []
count_results = []
def value_callback(old, new):
value_results.append((old, new))
def count_callback(old, new):
count_results.append((old, new))
bind(observable_data, "value", value_callback)
bind(observable_data, "count", count_callback)
unbind_all(observable_data)
observable_data.value = "first"
observable_data.count = 1
assert len(value_results) == 0
assert len(count_results) == 0
def test_i_cannot_unbind_all_from_non_observable_object(data):
"""
Trying to unbind_all from a non-observable object should raise NotObservableError.
"""
with pytest.raises(NotObservableError, match="must be made observable"):
unbind_all(data, "value")
def test_unbind_all_with_non_existent_attribute_is_safe(observable_data):
"""
unbind_all() with a non-existent attribute should not raise an error.
"""
# Should not raise
unbind_all(observable_data, "non_existent")
# ============================================================================
# has_listeners() tests
# ============================================================================
def test_has_listeners_returns_true_when_listeners_exist(observable_data):
"""
has_listeners() should return True when there are listeners.
"""
def callback(old, new):
pass
bind(observable_data, "value", callback)
assert has_listeners(observable_data, "value") is True
def test_has_listeners_returns_false_when_no_listeners(observable_data):
"""
has_listeners() should return False when there are no listeners.
"""
assert has_listeners(observable_data, "value") is False
def test_has_listeners_returns_false_after_unbind(observable_data):
"""
has_listeners() should return False after all listeners are removed.
"""
def callback(old, new):
pass
bind(observable_data, "value", callback)
assert has_listeners(observable_data, "value") is True
unbind(observable_data, "value", callback)
assert has_listeners(observable_data, "value") is False
def test_i_cannot_check_listeners_on_non_observable_object(data):
"""
Trying to check listeners on a non-observable object should raise NotObservableError.
"""
with pytest.raises(NotObservableError, match="must be made observable"):
has_listeners(data, "value")
# ============================================================================
# get_listener_count() tests
# ============================================================================
def test_get_listener_count_returns_zero_when_no_listeners(observable_data):
"""
get_listener_count() should return 0 when there are no listeners.
"""
assert get_listener_count(observable_data, "value") == 0
def test_get_listener_count_returns_correct_count(observable_data):
"""
get_listener_count() should return the correct number of listeners.
"""
def callback1(old, new):
pass
def callback2(old, new):
pass
def callback3(old, new):
pass
bind(observable_data, "value", callback1)
assert get_listener_count(observable_data, "value") == 1
bind(observable_data, "value", callback2)
assert get_listener_count(observable_data, "value") == 2
bind(observable_data, "value", callback3)
assert get_listener_count(observable_data, "value") == 3
def test_get_listener_count_decreases_after_unbind(observable_data):
"""
get_listener_count() should decrease after unbinding a callback.
"""
def callback1(old, new):
pass
def callback2(old, new):
pass
bind(observable_data, "value", callback1)
bind(observable_data, "value", callback2)
assert get_listener_count(observable_data, "value") == 2
unbind(observable_data, "value", callback1)
assert get_listener_count(observable_data, "value") == 1
unbind(observable_data, "value", callback2)
assert get_listener_count(observable_data, "value") == 0
def test_i_cannot_get_listener_count_on_non_observable_object(data):
"""
Trying to get listener count on a non-observable object should raise NotObservableError.
"""
with pytest.raises(NotObservableError, match="must be made observable"):
get_listener_count(data, "value")
# ============================================================================
# Integration tests
# ============================================================================
def test_multiple_bind_unbind_cycles(observable_data):
"""
Multiple bind/unbind cycles should work correctly.
"""
results = []
def callback(old, new):
results.append((old, new))
# Cycle 1
bind(observable_data, "value", callback)
observable_data.value = "first"
assert len(results) == 1
unbind(observable_data, "value", callback)
observable_data.value = "second"
assert len(results) == 1
# Cycle 2
bind(observable_data, "value", callback)
observable_data.value = "third"
assert len(results) == 2
unbind(observable_data, "value", callback)
observable_data.value = "fourth"
assert len(results) == 2
def test_same_callback_can_be_bound_to_multiple_attributes(observable_data):
"""
The same callback can be bound to multiple attributes and unbound independently.
"""
results = []
def callback(old, new):
results.append((old, new))
bind(observable_data, "value", callback)
bind(observable_data, "count", callback)
observable_data.value = "first"
observable_data.count = 1
assert len(results) == 2
unbind(observable_data, "value", callback)
observable_data.value = "second"
observable_data.count = 2
assert len(results) == 3 # Only count callback triggered