
import unittest
import user_code
import ast
import re   
import unittest
import importlib
import io
from contextlib import redirect_stdout

class TestTask(unittest.TestCase):
    def test_append_on_enter(self):
        import user_code
        importlib.reload(user_code)
        nums = [1, 2, 3]
        with user_code.temp_append(nums, 10):
            _dynamic_test(
                self,
                nums == [1, 2, 3, 10],
                "Appends item to list on enter",
                f"Expected [1, 2, 3, 10] inside context, got {nums}",
            )

    def test_remove_on_exit(self):
        import user_code
        importlib.reload(user_code)
        nums = [1, 2, 3]
        with user_code.temp_append(nums, 5):
            pass
        _dynamic_test(
            self,
            nums == [1, 2, 3],
            "Removes last occurrence of item on exit",
            f"Expected [1, 2, 3] after context, got {nums}",
        )

    def test_restore_on_exception(self):
        import user_code
        importlib.reload(user_code)
        nums = [7, 8, 9]
        try:
            with user_code.temp_append(nums, 42):
                raise ValueError("Oops!")
        except ValueError:
            pass
        _dynamic_test(
            self,
            nums == [7, 8, 9],
            "List restored after exception",
            f"Expected [7, 8, 9] after exception, got {nums}",
        )

    def test_multiple_identical_items(self):
        import user_code
        importlib.reload(user_code)
        nums = [1, 2, 3, 2]
        with user_code.temp_append(nums, 2):
            _dynamic_test(
                self,
                nums == [1, 2, 3, 2, 2],
                "Appends item even if already present",
                f"Expected [1, 2, 3, 2, 2] inside context, got {nums}",
            )
        _dynamic_test(
            self,
            nums == [1, 2, 3, 2],
            "Removes only last occurrence on exit",
            f"Expected [1, 2, 3, 2] after context, got {nums}",
        )

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

def normalize_text(text):
    text = text.lower()
    text = re.sub(r"\s{2,}", " ", text)
    text = re.sub(r"\s*([,:?])\s*", r"\1 ", text)
    return text.strip()

def change_var(code: str, var_name: str, value: str) -> str:
    tree = ast.parse(code)
    lines = code.splitlines()
    for i, node in enumerate(tree.body):
        if isinstance(node, ast.Assign):
            for target in node.targets:
                if isinstance(target, ast.Name) and target.id == var_name:
                    start_line = node.lineno - 1
                    line = lines[start_line]
                    indent = ' ' * (len(line) - len(line.lstrip()))
                    lines[start_line] = f"{indent}{var_name} = {value}"
                    next_line = len(lines)
                    for next_node in tree.body[i+1:]:
                        if hasattr(next_node, 'lineno'):
                            next_line = next_node.lineno - 1
                            break
                    if next_line > start_line + 1:
                        lines[start_line+1:next_line] = []
                    
                    return '\\n'.join(lines)
    return code

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


test_main.py

Master the art of resource management in Python by learning how to use and create context managers. This course covers the underlying protocol, practical applications, and advanced techniques for robust and efficient code.

Explore the fundamentals of context managers, their protocol, and how they simplify resource management in Python.

Delve into creating your own context managers using both classes and generator functions.

Solidify your understanding by tackling practical tasks that require context managers in various scenarios.

Challenge: Temporary List Modification

Solution