From d62b135cee6196a21b50e23fbc7e62622782d458 Mon Sep 17 00:00:00 2001
From: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date: Sun, 2 Nov 2025 18:10:57 +0100
Subject: [PATCH] Added `unbind`, `unbind_all`, `has_listeners`
 `get_listener_count`

---
 README.md                 | 173 +++++++++++-
 pyproject.toml            |   2 +-
 src/myutils/observable.py | 225 +++++++++++++++
 tests/test_observable.py  | 566 ++++++++++++++++++++++++++++++++------
 4 files changed, 877 insertions(+), 89 deletions(-)

diff --git a/README.md b/README.md
index 7d2bed8..9e57dff 100644
--- a/README.md
+++ b/README.md
@@ -29,14 +29,24 @@ occurs.
 - `bind(object, attribute, callback)`:
   Adds a callback function to an observable object's attribute. The callback is triggered when the attribute value
   changes.
+- `unbind(object, attribute, callback)`:
+  Removes a callback from an observable object's attribute.
+- `unbind_all(object, attribute)`:
+  Removes all callbacks from an observable object's attribute.
+- `has_listeners(object, attribute)`:
+  Checks if an observable object has any listeners for a specific attribute.
+- `get_listener_count(object, attribute)`:
+  Returns the number of listeners for a specific attribute on an observable object.
 - Exception: `NotObservableError` is raised if you attempt to bind a callback to a non-observable object.
 
 #### Example Usage:
 
+#### Basic Usage
+
 Here is an example using the `Observable` module:
 
 ```python
-from myutils.observable import make_observable, bind
+from myutils.observable import make_observable, bind, unbind
 
 
 class Demo:
@@ -47,11 +57,162 @@ class Demo:
 demo = Demo()
 make_observable(demo)
 
+l = lambda old, new: print(f"Changed from {old} to {new}")
+
 # Bind a callback to 'number'
-bind(demo, 'number', lambda old, new: print(f"Changed from {old} to {new}"))
+bind(demo, 'number', l)
 
 # Updating an attribute triggers the callback
 demo.number = 42  # Output: Changed from 1 to 42
+
+# Unbind the callback
+unbind(demo, 'number', l)
+demo.number = 43  # No output
+```
+
+#### Multiple Callbacks
+
+```python
+from dataclasses import dataclass
+from myutils.observable import make_observable, bind, unbind
+
+
+@dataclass
+class Data:
+  value: str = "hello"
+
+
+data = Data()
+
+
+def callback1(old, new):
+  print(f"Callback1: {old} -> {new}")
+
+
+def callback2(old, new):
+  print(f"Callback2: {old} -> {new}")
+
+
+# Bind both
+bind(data, "value", callback1)
+bind(data, "value", callback2)
+
+data.value = "test"
+# Prints:
+# Callback1: hello -> test
+# Callback2: hello -> test
+
+# Remove only one
+unbind(data, "value", callback1)
+
+data.value = "final"
+# Prints:
+# Callback2: test -> final
+```
+
+#### Multiple Callbacks
+
+```python
+from dataclasses import dataclass
+from myutils.observable import make_observable, bind, unbind
+
+
+@dataclass
+class Data:
+  value: str = "hello"
+
+
+data = Data()
+
+
+def callback1(old, new):
+  print(f"Callback1: {old} -> {new}")
+
+
+def callback2(old, new):
+  print(f"Callback2: {old} -> {new}")
+
+
+# Bind both
+bind(data, "value", callback1)
+bind(data, "value", callback2)
+
+data.value = "test"
+# Prints:
+# Callback1: hello -> test
+# Callback2: hello -> test
+
+# Remove only one
+unbind(data, "value", callback1)
+
+data.value = "final"
+# Prints:
+# Callback2: test -> final
+```
+
+#### Using Helper Functions
+
+```python
+from dataclasses import dataclass
+from myutils.observable import has_listeners, get_listener_count, unbind_all
+
+
+@dataclass
+class Data:
+  value: str = "hello"
+
+
+data = Data()
+
+# Check if attribute has listeners
+if has_listeners(data, "value"):
+  print("Value has listeners")
+
+# Get count
+count = get_listener_count(data, "value")
+print(f"Value has {count} listeners")
+
+# Remove all listeners from one attribute
+unbind_all(data, "value")
+
+# Remove all listeners from all attributes
+unbind_all(data)
+```
+
+### Common Pitfalls
+
+#### ❌ Wrong: Using different callback instance
+
+```python
+bind(data, "value", lambda old, new: print(old))
+unbind(data, "value", lambda old, new: print(old))  # Different lambda!
+# The callback is NOT removed because lambdas are different objects
+```
+
+#### ✅ Correct: Using same callback reference
+
+```python
+callback = lambda old, new: print(old)
+bind(data, "value", callback)
+unbind(data, "value", callback)  # Same reference
+# Callback is properly removed
+```
+
+#### ❌ Wrong: Assuming unbind raises on missing callback
+
+```python
+try:
+  unbind(data, "value", non_existent_callback)
+except Exception:
+  # This won't execute - unbind fails silently
+  pass
+```
+
+#### ✅ Correct: Check before unbinding if needed
+
+```python
+if has_listeners(data, "value"):
+  unbind(data, "value", callback)
 ```
 
 ---
@@ -110,8 +271,9 @@ MyUtils
 │       └── __init__.py         # Main package initialization
 ├── tests
 │   ├── __init__.py             # Test package initialization
-│   ├── test_observable.py      # Tests for Observable module
-│   └── test_expando.py         # Tests for Expando module
+│   ├── test_dummy.py           # Tests for Dummy module
+│   ├── test_expando.py         # Tests for Expando module
+│   └── test_observable.py      # Tests for Observable module
 ├── .gitignore                  # Git ignore file
 ├── main.py                     # Application entry point
 ├── requirements.txt            # Project dependencies
@@ -156,4 +318,5 @@ Special thanks to the Python and open-source community for their tools, inspirat
 ## Release History
 
 * 0.1.0 : Initial release
-* 0.2.0 : Observable results can be collected using `collect_return_values`
\ No newline at end of file
+* 0.2.0 : Observable results can be collected using `collect_return_values`
+* 0.3.0 : Added `unbind`, `unbind_all`, `has_listeners` `get_listener_count` to Observable
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index 8e7a2cf..4600384 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "myutils"
-version = "0.2.0"
+version = "0.3.0"
 description = "Base useful classes."
 readme = "README.md"
 authors = [
diff --git a/src/myutils/observable.py b/src/myutils/observable.py
index c3db3c6..5a67e10 100644
--- a/src/myutils/observable.py
+++ b/src/myutils/observable.py
@@ -46,3 +46,228 @@ def bind(obj, attr_name, callback):
   if attr_name not in obj._listeners:
     obj._listeners[attr_name] = []
   obj._listeners[attr_name].append(callback)
+
+
+"""
+Implementation of unbind() function for myutils.observable module.
+
+This implementation is adapted to work with the existing make_observable()
+and bind() functions that use the _listeners dictionary pattern.
+"""
+
+
+def unbind(obj, attr_name, callback):
+  """
+  Remove a specific callback from an observable attribute.
+
+  This function removes a previously registered callback for an attribute
+  of an observable object. It should be called with the same parameters
+  that were used with bind().
+
+  Args:
+      obj: The observable object (must have been made observable with make_observable())
+      attr_name: The attribute name to stop observing
+      callback: The exact callback function to remove (must be the same object)
+
+  Raises:
+      NotObservableError: If the object is not observable
+
+  Example:
+      >>> from myutils.observable import make_observable, bind, unbind
+      >>>
+      >>> @dataclass
+      >>> class Data:
+      ...     value: str = "hello"
+      >>>
+      >>> def my_callback(old, new):
+      ...     print(f"Changed from {old} to {new}")
+      >>>
+      >>> data = Data()
+      >>> make_observable(data)
+      >>> bind(data, "value", my_callback)
+      >>>
+      >>> data.value = "world"  # Prints: Changed from hello to world
+      >>>
+      >>> unbind(data, "value", my_callback)
+      >>> data.value = "foo"  # Does not print anything
+
+  Notes:
+      - If the callback is not found, this function fails silently
+      - If the attribute has no callbacks registered, fails silently
+      - The callback parameter must be the exact same function object
+        that was passed to bind()
+      - After removing the last callback for an attribute, the attribute
+        key remains in _listeners as an empty list (for performance)
+  """
+  if not hasattr(obj, '_listeners'):
+    raise NotObservableError(
+      f"Object must be made observable with make_observable() before unbinding"
+    )
+  
+  # Check if attribute has any listeners
+  if attr_name not in obj._listeners:
+    # No listeners for this attribute, nothing to do
+    return
+  
+  # Try to remove the callback
+  try:
+    obj._listeners[attr_name].remove(callback)
+  except ValueError:
+    # Callback not found in the list, fail silently
+    pass
+
+
+def unbind_all(obj, attr_name=None):
+  """
+  Remove all callbacks from an object or a specific attribute.
+
+  Args:
+      obj: The observable object
+      attr_name: Optional attribute name. If None, removes all callbacks
+                from all attributes. If specified, removes all callbacks
+                from that specific attribute only.
+
+  Raises:
+      NotObservableError: If the object is not observable
+
+  Example:
+      >>> # Remove all callbacks from a specific attribute
+      >>> unbind_all(data, "value")
+      >>>
+      >>> # Remove all callbacks from all attributes
+      >>> unbind_all(data)
+  """
+  if not hasattr(obj, '_listeners'):
+    raise NotObservableError(
+      f"Object must be made observable with make_observable() before unbinding"
+    )
+  
+  if attr_name is None:
+    # Remove all callbacks from all attributes
+    obj._listeners.clear()
+  elif attr_name in obj._listeners:
+    # Remove all callbacks from specific attribute
+    obj._listeners[attr_name].clear()
+
+
+def has_listeners(obj, attr_name):
+  """
+  Check if an attribute has any listeners.
+
+  Args:
+      obj: The observable object
+      attr_name: The attribute name to check
+
+  Returns:
+      bool: True if the attribute has at least one listener
+
+  Raises:
+      NotObservableError: If the object is not observable
+
+  Example:
+      >>> make_observable(data)
+      >>> bind(data, "value", callback)
+      >>> has_listeners(data, "value")
+      True
+      >>> unbind(data, "value", callback)
+      >>> has_listeners(data, "value")
+      False
+  """
+  if not hasattr(obj, '_listeners'):
+    raise NotObservableError(
+      f"Object must be made observable with make_observable() before checking listeners"
+    )
+  
+  return attr_name in obj._listeners and len(obj._listeners[attr_name]) > 0
+
+
+def get_listener_count(obj, attr_name):
+  """
+  Get the number of listeners for a specific attribute.
+
+  Args:
+      obj: The observable object
+      attr_name: The attribute name to check
+
+  Returns:
+      int: Number of listeners registered for the attribute
+
+  Raises:
+      NotObservableError: If the object is not observable
+
+  Example:
+      >>> make_observable(data)
+      >>> bind(data, "value", callback1)
+      >>> bind(data, "value", callback2)
+      >>> get_listener_count(data, "value")
+      2
+  """
+  if not hasattr(obj, '_listeners'):
+    raise NotObservableError(
+      f"Object must be made observable with make_observable() before getting listener count"
+    )
+  
+  if attr_name not in obj._listeners:
+    return 0
+  
+  return len(obj._listeners[attr_name])
+
+
+# Complete example of usage
+if __name__ == "__main__":
+  from dataclasses import dataclass
+  
+  
+  @dataclass
+  class Data:
+    value: str = "hello"
+    count: int = 0
+  
+  
+  # Create observable
+  data = Data()
+  make_observable(data)
+  
+  
+  # Define callbacks
+  def callback1(old, new):
+    print(f"Callback1: {old} -> {new}")
+    return "callback1_result"
+  
+  
+  def callback2(old, new):
+    print(f"Callback2: {old} -> {new}")
+    return "callback2_result"
+  
+  
+  # Bind callbacks
+  bind(data, "value", callback1)
+  bind(data, "value", callback2)
+  
+  print("=== Both callbacks active ===")
+  data.value = "world"
+  # Prints:
+  # Callback1: hello -> world
+  # Callback2: hello -> world
+  
+  print(f"Listener count: {get_listener_count(data, 'value')}")  # 2
+  
+  # Unbind one callback
+  unbind(data, "value", callback1)
+  
+  print("\n=== Only callback2 active ===")
+  data.value = "foo"
+  # Prints:
+  # Callback2: world -> foo
+  
+  print(f"Listener count: {get_listener_count(data, 'value')}")  # 1
+  
+  # Unbind remaining callback
+  unbind(data, "value", callback2)
+  
+  print("\n=== No callbacks active ===")
+  data.value = "bar"
+  # Prints nothing
+  
+  print(f"Has listeners: {has_listeners(data, 'value')}")  # False
+  print(f"Listener count: {get_listener_count(data, 'value')}")  # 0
diff --git a/tests/test_observable.py b/tests/test_observable.py
index 34636ea..25dd9dd 100644
--- a/tests/test_observable.py
+++ b/tests/test_observable.py
@@ -1,207 +1,607 @@
 import pytest
 
-from myutils.observable import NotObservableError, make_observable, bind, collect_return_values
+from myutils.observable import NotObservableError, make_observable, bind, collect_return_values, unbind, unbind_all, \
+  has_listeners, get_listener_count
 
 
 # Test fixtures
-class Demo:
+class Data:
   def __init__(self):
-    self.number = 1
+    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():
-  demo = Demo()
-  result = make_observable(demo)
-  
-  assert hasattr(demo, '_listeners')
-  assert isinstance(demo._listeners, dict)
-  assert result is demo
+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():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   callback = lambda old, new: None
-  bind(demo, 'number', callback)
+  bind(data, 'number', callback)
   
-  assert 'number' in demo._listeners
-  assert callback in demo._listeners['number']
+  assert 'number' in data._listeners
+  assert callback in data._listeners['number']
 
 
 def test_i_can_receive_notification_when_attribute_changes():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   called = []
-  bind(demo, 'number', lambda old, new: called.append(True))
+  bind(data, 'number', lambda old, new: called.append(True))
   
-  demo.number = 5
+  data.number = 5
   
   assert len(called) == 1
 
 
 def test_i_can_receive_old_and_new_values_in_callback():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   values = []
-  bind(demo, 'number', lambda old, new: values.append((old, new)))
+  bind(data, 'number', lambda old, new: values.append((old, new)))
   
-  demo.number = 5
-  demo.number = 10
+  data.number = 5
+  data.number = 10
   
   assert values == [(1, 5), (5, 10)]
 
 
 def test_i_can_bind_multiple_callbacks_to_same_attribute():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   calls1 = []
   calls2 = []
-  bind(demo, 'number', lambda old, new: calls1.append(new))
-  bind(demo, 'number', lambda old, new: calls2.append(new))
+  bind(data, 'number', lambda old, new: calls1.append(new))
+  bind(data, 'number', lambda old, new: calls2.append(new))
   
-  demo.number = 5
+  data.number = 5
   
   assert calls1 == [5]
   assert calls2 == [5]
 
 
 def test_i_can_bind_callbacks_to_different_attributes():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   number_calls = []
   name_calls = []
-  bind(demo, 'number', lambda old, new: number_calls.append(new))
-  bind(demo, 'name', lambda old, new: name_calls.append(new))
+  bind(data, 'number', lambda old, new: number_calls.append(new))
+  bind(data, 'name', lambda old, new: name_calls.append(new))
   
-  demo.number = 5
-  demo.name = "test"
+  data.number = 5
+  data.name = "test"
   
   assert number_calls == [5]
   assert name_calls == ["test"]
 
 
 def test_i_can_modify_non_observed_attributes_without_notification():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   called = []
-  bind(demo, 'number', lambda old, new: called.append(True))
+  bind(data, 'number', lambda old, new: called.append(True))
   
-  demo.other_attr = "value"
+  data.other_attr = "value"
   
   assert len(called) == 0
-  assert demo.other_attr == "value"
+  assert data.other_attr == "value"
 
 
 def test_i_can_have_multiple_instances_with_independent_observers():
-  demo1 = Demo()
-  demo2 = Demo()
+  data1 = Data()
+  data2 = Data()
   
-  make_observable(demo1)
+  make_observable(data1)
   
   calls1 = []
-  bind(demo1, 'number', lambda old, new: calls1.append(new))
+  bind(data1, 'number', lambda old, new: calls1.append(new))
   
-  demo1.number = 5
-  demo2.number = 10
+  data1.number = 5
+  data2.number = 10
   
-  # Only demo1 should trigger callback
+  # Only data1 should trigger callback
   assert calls1 == [5]
-  assert demo1.number == 5
-  assert demo2.number == 10
+  assert data1.number == 5
+  assert data2.number == 10
 
 
 def test_i_can_call_make_observable_multiple_times_safely():
-  demo = Demo()
+  data = Data()
   
-  result1 = make_observable(demo)
-  result2 = make_observable(demo)
+  result1 = make_observable(data)
+  result2 = make_observable(data)
   
   assert result1 is result2
-  assert hasattr(demo, '_listeners')
+  assert hasattr(data, '_listeners')
   
   # Should still work normally
   called = []
-  bind(demo, 'number', lambda old, new: called.append(new))
-  demo.number = 5
+  bind(data, 'number', lambda old, new: called.append(new))
+  data.number = 5
   
   assert len(called) == 1
 
 
 def test_i_cannot_bind_before_making_observable():
-  demo = Demo()
+  data = Data()
   
   with pytest.raises(NotObservableError) as exc_info:
-    bind(demo, 'number', lambda old, new: None)
+    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():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   values = []
-  bind(demo, 'new_attr', lambda old, new: values.append((old, new)))
+  bind(data, 'new_attr', lambda old, new: values.append((old, new)))
   
-  demo.new_attr = "first_value"
+  data.new_attr = "first_value"
   
   assert values == [(None, "first_value")]
-  assert demo.new_attr == "first_value"
+  assert data.new_attr == "first_value"
 
 
 def test_i_can_preserve_original_class_behavior():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
   # Test that original methods still work
-  assert demo.get_double() == 2
+  assert data.get_double() == 2
   
-  demo.number = 5
-  assert demo.get_double() == 10
+  data.number = 5
+  assert data.get_double() == 10
   
   # Test that isinstance still works
-  assert isinstance(demo, Demo)
+  assert isinstance(data, Data)
 
 
 def test_i_can_collect_the_updates():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
-  bind(demo, 'number', lambda old, new: new)
-  bind(demo, 'number', lambda old, new: new * 2)
+  bind(data, 'number', lambda old, new: new)
+  bind(data, 'number', lambda old, new: new * 2)
   
-  demo.number = 5
-  assert collect_return_values(demo) == [5, 10]
+  data.number = 5
+  assert collect_return_values(data) == [5, 10]
   
   # another time to make sure there is no side effect
-  demo.number = 10
-  assert collect_return_values(demo) == [10, 20]
+  data.number = 10
+  assert collect_return_values(data) == [10, 20]
 
 
 def test_i_cannot_collect_updates_before_making_observable():
-  demo = Demo()
+  data = Data()
   
   with pytest.raises(NotObservableError) as exc_info:
-    collect_return_values(demo)
+    collect_return_values(data)
   
   assert "must be made observable" in str(exc_info.value).lower()
 
 
 def test_i_can_collect_none():
-  demo = Demo()
-  make_observable(demo)
+  data = Data()
+  make_observable(data)
   
-  bind(demo, 'number', lambda old, new: None)
+  bind(data, 'number', lambda old, new: None)
   
-  demo.number = 5
-  assert collect_return_values(demo) == [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