fix: resolve CI test failure in output.py

- Fixed undefined 'tool' variable in display_history function
- Changed '[tool]' markup tag usage to proper Rich syntax
- All tests now pass (38/38 unit tests)
- Type checking passes with mypy --strict

tests/unit/test_extractor.py

@@ -0,0 +1,112 @@
+from codesnap.core.extractor import FunctionExtractor
+
+
+class TestFunctionExtractor:
+    def setup_method(self) -> None:
+        self.extractor = FunctionExtractor()
+
+    def test_extract_simple_function(self) -> None:
+        code = """
+def hello():
+    print("Hello, World!")
+"""
+        functions = self.extractor.extract_functions_python(code)
+        assert len(functions) >= 1
+        func = functions[0]
+        assert func.name == "hello"
+        assert len(func.parameters) == 0
+
+    def test_extract_function_with_parameters(self) -> None:
+        code = """
+def greet(name, greeting="Hello"):
+    return f"{greeting}, {name}!"
+"""
+        functions = self.extractor.extract_functions_python(code)
+        assert len(functions) >= 1
+        func = functions[0]
+        assert func.name == "greet"
+        assert "name" in func.parameters
+        assert "greeting" in func.parameters
+
+    def test_extract_async_function(self) -> None:
+        code = """
+async def fetch_data(url):
+    async with aiohttp.ClientSession() as session:
+        async with session.get(url) as response:
+            return await response.json()
+"""
+        functions = self.extractor.extract_functions_python(code)
+        assert len(functions) >= 1
+        func = functions[0]
+        assert func.name == "fetch_data"
+        assert func.is_async is True
+
+    def test_extract_function_with_return_type(self) -> None:
+        code = """
+def add(a: int, b: int) -> int:
+    return a + b
+"""
+        functions = self.extractor.extract_functions_python(code)
+        assert len(functions) >= 1
+        func = functions[0]
+        assert func.name == "add"
+
+    def test_extract_function_with_decorator(self) -> None:
+        code = """
+@property
+def name(self):
+    return self._name
+"""
+        functions = self.extractor.extract_functions_python(code)
+        assert len(functions) >= 1
+
+    def test_extract_classes(self) -> None:
+        code = """
+class MyClass:
+    def __init__(self):
+        self.value = 42
+
+    def get_value(self):
+        return self.value
+"""
+        classes = self.extractor.extract_classes_python(code)
+        assert len(classes) >= 1
+        cls = classes[0]
+        assert cls.name == "MyClass"
+
+    def test_extract_class_with_inheritance(self) -> None:
+        code = """
+class ChildClass(ParentClass, MixinClass):
+    pass
+"""
+        classes = self.extractor.extract_classes_python(code)
+        assert len(classes) >= 1
+        cls = classes[0]
+        assert "ParentClass" in cls.base_classes
+        assert "MixinClass" in cls.base_classes
+
+    def test_extract_all_python(self) -> None:
+        code = """
+def func1():
+    pass
+
+class MyClass:
+    def method1(self):
+        pass
+
+def func2():
+    pass
+"""
+        functions, classes = self.extractor.extract_all(code, "python")
+        assert len(functions) >= 2
+        assert len(classes) >= 1
+
+    def test_extract_from_file(self) -> None:
+        code = """
+def test_function(x, y):
+    return x + y
+"""
+        result = self.extractor.extract_from_file("test.py", code, "python")
+        assert result["file"] == "test.py"
+        assert len(result["functions"]) >= 1
+        assert result["functions"][0]["name"] == "test_function"