
import unittest
import io
import sys
import re
import importlib

class TestTask(unittest.TestCase):
    def test_log_calls_prints_function_name_and_args(self):
        import user_code
        importlib.reload(user_code)
        f = io.StringIO()
        sys_stdout = sys.stdout
        sys.stdout = f
        result = user_code.multiply(3, 4)
        sys.stdout = sys_stdout
        output = f.getvalue()
        log_pattern = r"Calling function 'multiply' with args=\\(3, 4\\), kwargs=\\{\\}"
        _dynamic_test(
            self,
            re.search(log_pattern, output) is not None,
            "log_calls prints function name and arguments",
            f"Expected log message not found in output: {output}",
        )

    def test_time_execution_prints_timing(self):
        import user_code
        importlib.reload(user_code)
        f = io.StringIO()
        sys_stdout = sys.stdout
        sys.stdout = f
        user_code.multiply(8, 2)
        sys.stdout = sys_stdout
        output = f.getvalue()
        timing_pattern = r"Function 'multiply' executed in (\\d+\\.\\d{6}) seconds"
        _dynamic_test(
            self,
            re.search(timing_pattern, output) is not None,
            "time_execution prints execution time to six decimal places",
            f"Timing message with six decimals not found in output: {output}",
        )

    def test_multiply_returns_correct_product(self):
        import user_code
        importlib.reload(user_code)
        result = user_code.multiply(6, 9)
        _dynamic_test(
            self,
            result == 54,
            "multiply returns correct product for (6, 9)",
            f"Expected 54 but got {result}",
        )

    def test_log_calls_before_time_execution(self):
        import user_code
        importlib.reload(user_code)
        f = io.StringIO()
        sys_stdout = sys.stdout
        sys.stdout = f
        user_code.multiply(2, 5)
        sys.stdout = sys_stdout
        output = f.getvalue().splitlines()
        log_index = None
        timing_index = None
        for i, line in enumerate(output):
            if "Calling function 'multiply'" in line:
                log_index = i
            if "executed in" in line:
                timing_index = i
        _dynamic_test(
            self,
            log_index is not None and timing_index is not None and log_index < timing_index,
            "Logging output appears before timing output",
            f"Expected logging before timing, got: {output}",
        )

    def test_multiple_calls_with_different_args(self):
        import user_code
        importlib.reload(user_code)
        f = io.StringIO()
        sys_stdout = sys.stdout
        sys.stdout = f
        res1 = user_code.multiply(1, 2)
        res2 = user_code.multiply(10, 20)
        sys.stdout = sys_stdout
        output = f.getvalue()
        log1 = "Calling function 'multiply' with args=(1, 2), kwargs={}"
        log2 = "Calling function 'multiply' with args=(10, 20), kwargs={}"
        _dynamic_test(
            self,
            log1 in output and log2 in output and res1 == 2 and res2 == 200,
            "Decorators handle multiple calls and correct output",
            f"Expected log messages for both calls and correct results. Output: {output}, Results: {res1}, {res2}",
        )

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:
    import ast
    tree = ast.parse(code)
    lines = code.splitlines()
    changed = False
    assign_nodes = [
        (i, node)
        for i, node in enumerate(tree.body)
        if isinstance(node, ast.Assign)
        and any(isinstance(target, ast.Name) and target.id == var_name for target in node.targets)
    ]
    if not assign_nodes:
        return code
    for i, node in reversed(assign_nodes):
        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] = []
        changed = True
    return '\\n'.join(lines) if changed else code

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


test_main.py

Master packing/unpacking, flexible function arguments, higher-order functions, lambdas, variable scope, closures, iterators and decorators. Designed for learners who have completed an introductory Python course and want to write more efficient, expressive, and powerful code.

Explore the art of packing and unpacking lists, tuples, and dictionaries to write more expressive and efficient Python code.

Delve into the world of higher-order functions, passing functions as arguments, and writing concise anonymous functions with lambda.

Unravel the mysteries of variable scope, and learn how nested functions and closures enable powerful encapsulation.

Delve into Python's iteration protocol, custom iterators, and generator functions for efficient data processing.

Challenge: Logging and Timing Decorators

Solution