
import unittest
import user_code
import ast
import re   
import importlib
import csv
import unittest
import importlib
import io
import sys
import asyncio
from contextlib import redirect_stdout
import time

class TestTask(unittest.TestCase):
    def setUp(self):
        # Reload user_code fresh for each test
        self.user_code = importlib.import_module('user_code')
        importlib.reload(self.user_code)

    def test_simulate_web_request_output(self):
        # Patch asyncio.sleep to speed up test
        original_sleep = asyncio.sleep
        async def fast_sleep(delay):
            return await original_sleep(0)
        self.user_code.asyncio.sleep = fast_sleep

        f = io.StringIO()
        with redirect_stdout(f):
            asyncio.run(self.user_code.main())
        output = normalize_text(f.getvalue())
        # Check for all required output lines
        for req, delay in [('Request-A', '2'), ('Request-B', '1'), ('Request-C', '3')]:
            expected = normalize_text(f"{req} completed after {delay} seconds")
            _dynamic_test(
                self,
                expected in output,
                f"Output contains: {expected}",
                f"Missing output: {expected}"
            )

    def test_requests_run_concurrently(self):
        # This test checks that the total runtime is less than the sum of all delays
        # i.e., requests are concurrent, not sequential
        start = time.time()
        asyncio.run(self.user_code.main())
        elapsed = time.time() - start
        # Sequential would be 2+1+3=6, concurrent should be just over 3
        _dynamic_test(
            self,
            elapsed < 5,
            "Requests run concurrently (total time < 5 seconds)",
            f"Requests did not run concurrently (elapsed: {elapsed:.2f} seconds)"
        )

    def test_function_signatures(self):
        # Check that function signatures are not changed
        import inspect
        sig = inspect.signature(self.user_code.simulate_web_request)
        params = list(sig.parameters.keys())
        _dynamic_test(
            self,
            params == ['name', 'delay'],
            "Function signature for simulate_web_request is unchanged.",
            f"simulate_web_request signature changed: {params}"
        )
        sig_main = inspect.signature(self.user_code.main)
        _dynamic_test(
            self,
            list(sig_main.parameters.keys()) == [],
            "main() signature is unchanged.",
            f"main signature should have no parameters, got: {list(sig_main.parameters.keys())}"
        )

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()
    changed = False
    # Collect all assignment nodes to modify
    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 nothing to change, return unmodified code
    if not assign_nodes:
        return code

    # Perform replacements for all matching assignments (from last to first to not break line offsets)
    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

A deep dive into advanced structural programming concepts in Python, focusing on robust file handling, error management, concurrency, asynchronous programming and testing.

Master Python's exception system for robust error handling and debugging.

Explore advanced techniques for file operations and resource management using context managers.

Compare and apply Python's multithreading and multiprocessing modules for concurrent programming.

Master asynchronous programming in Python using the asyncio library for scalable I/O-bound applications.

Explore how to write, organize, and run tests using Python's unittest and pytest frameworks.

Challenge: Async Web Request Simulator

Solution