
To practice applying advanced regular expression techniques, you will create a password validator that checks if a password is **strong**. 

Write a function called `is_strong_password(password)` that returns `True` if the password meets all these requirements, and `False` otherwise. Use regular expressions to perform the necessary checks.


import unittest
import user_code
import ast
import re   
import unittest
import importlib

class TestTask(unittest.TestCase):
    def test_valid_strong_password(self):
        import user_code
        importlib.reload(user_code)
        password = "Abcdef1$"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is True,
            "Correctly returns True for valid strong password.",
            f"Expected True for password '{password}', got {result}.",
        )

    def test_too_short(self):
        import user_code
        importlib.reload(user_code)
        password = "Ab1$e"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is False,
            "Correctly returns False for password shorter than 8 characters.",
            f"Expected False for short password '{password}', got {result}.",
        )

    def test_missing_uppercase(self):
        import user_code
        importlib.reload(user_code)
        password = "abcdef1$"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is False,
            "Correctly returns False for password missing uppercase letter.",
            f"Expected False for password missing uppercase '{password}', got {result}.",
        )

    def test_missing_lowercase(self):
        import user_code
        importlib.reload(user_code)
        password = "ABCDEFG1$"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is False,
            "Correctly returns False for password missing lowercase letter.",
            f"Expected False for password missing lowercase '{password}', got {result}.",
        )

    def test_missing_digit(self):
        import user_code
        importlib.reload(user_code)
        password = "Abcdefg$"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is False,
            "Correctly returns False for password missing digit.",
            f"Expected False for password missing digit '{password}', got {result}.",
        )

    def test_missing_special_character(self):
        import user_code
        importlib.reload(user_code)
        password = "Abcdefg1"
        result = user_code.is_strong_password(password)
        _dynamic_test(
            self,
            result is False,
            "Correctly returns False for password missing special character.",
            f"Expected False for password missing special character '{password}', got {result}.",
        )

    def test_special_characters_variety(self):
        import user_code
        importlib.reload(user_code)
        passwords = ["Abcdef1@", "Abcdef1#", "Abcdef1!", "Abcdef1_"]
        for pw in passwords:
            result = user_code.is_strong_password(pw)
            _dynamic_test(
                self,
                result is True,
                f"Correctly returns True for strong password '{pw}'.",
                f"Expected True for strong password '{pw}', got {result}.",
            )

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

A focused, hands-on course on using Python regular expressions for automating data extraction, cleaning, and transformation tasks. This course skips introductory repetition and dives into practical pattern matching, substitution, and real-world automation scenarios, making it ideal for beginners aiming to automate structured and unstructured data processing.

Challenge: Validate Strong Passwords

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