**Congratulations** on reaching this point in the course! In this capstone challenge, you will **manage perishable products** at a grocery store, determining discounts based on product expiration and stock levels. Your goal is to minimize waste while effectively maximizing sales through strategic discounting. 

Let's see how well you can translate business rules into Python code!

## Scenario

As a manager at a grocery store, you are responsible for **implementing a discount strategy** for perishable products based on their expiration date and stock levels. 

The discount strategy is as follows:

- Apply a **30%** discount if the product **expires in 3 days** or less and the stock level is **over** `50` units;
- Apply a **20%** discount if the product **expires in 4 to 6 days** and the stock level is **over** `50` units;
- Apply a **10%** discount if the product **expires in 7 days or more**, or if the stock level is `50` units or **less**;
- **No discount** if the product is not "Perishable".


import unittest
import io
import re
from contextlib import redirect_stdout


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 strip_comments_from_source(path):
    try:
        with open(path, 'r') as file:
            source = file.read()
        lines = source.split('\\n')
        cleaned = []
        for line in lines:
            stripped = line.strip()
            if stripped.startswith('#'):
                continue
            if '#' in line:
                line = line.split('#')[0]
            if line.strip():
                cleaned.append(line)
        return '\\n'.join(cleaned)
    except Exception:
        return ""


class TestPerishableDiscounts(unittest.TestCase):

    def normalize_text(self, text):
        text = text.lower()
        text = re.sub(r'\s+', ' ', text)
        text = re.sub(r'\s*([,:?%])\s*', r'\1 ', text)
        return text.strip()

    def run_code_with_inputs(self, product_type, days, stock):
        with open('user_code.py', 'r') as f:
            code = f.read()

        # ÐÐ¾Ð´ÑÑÐ°Ð½Ð¾Ð²ÐºÐ° Ð²ÑÐ¾Ð´Ð½ÑÑ Ð·Ð½Ð°ÑÐµÐ½Ð¸Ð¹
        code = re.sub(r'days_until_expiration\s*=\s*\d+', f'days_until_expiration = {days}', code)
        code = re.sub(r'stock_level\s*=\s*\d+', f'stock_level = {stock}', code)
        code = re.sub(r'product_type\s*=\s*["\\\'].*?["\\\']', f'product_type = "{product_type}"', code)

        f = io.StringIO()
        with redirect_stdout(f):
            exec(code, {})
        return self.normalize_text(f.getvalue())

    def test_30_percent_discount(self):
        output = self.run_code_with_inputs("Perishable", 2, 51)
        expected = self.normalize_text("30% discount applied")
        _dynamic_test(
            self,
            expected in output,
            "30% discount applied for <=3 days and stock > 50",
            f"Expected: '{expected}', got: '{output}'"
        )

    def test_20_percent_discount(self):
        output = self.run_code_with_inputs("Perishable", 5, 55)
        expected = self.normalize_text("20% discount applied")
        _dynamic_test(
            self,
            expected in output,
            "20% discount applied for 4 to 6 days and stock > 50",
            f"Expected: '{expected}', got: '{output}'"
        )

    def test_10_percent_discount(self):
        output = self.run_code_with_inputs("Perishable", 7, 50)
        expected = self.normalize_text("10% discount applied")
        _dynamic_test(
            self,
            expected in output,
            "10% discount applied for >6 days and stock <= 50",
            f"Expected: '{expected}', got: '{output}'"
        )

    def test_non_perishable_no_discount(self):
        output = self.run_code_with_inputs("Non-Perishable", 2, 100)
        expected = self.normalize_text("No discount available for non-perishable items.")
        _dynamic_test(
            self,
            expected in output,
            "No discount applied for non-perishable item",
            f"Expected: '{expected}', got: '{output}'"
        )

    def test_nested_conditionals_used(self):
        source = strip_comments_from_source("user_code.py")
        has_nested_if = re.search(r'if', source)
        _dynamic_test(
            self,
            has_nested_if is not None,
            "Nested if-statements are used inside main product_type check",
            "Expected nested 'if' inside 'if product_type == \\\"Perishable\\\"'"
        )


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

test_main.py

Python is a high-level, interpreted, general-purpose programming
language. Distinguished from languages such as HTML, CSS, and JavaScript, which are mainly
utilized in web development, Python boasts versatility across multiple domains, including
software development, data science, and back-end development. This course will guide you
through Python's fundamental concepts, equipping you with the skills to create your own
functions by the conclusion of the program.

In this section, you will explore the fundamentals of Python, get acquainted
with your workspace, perform simple math operations, and display your findings.

In this section, you'll discover how to save items such as numbers and text
in computer memory and retrieve them by name. Additionally, you'll gain an introduction to text
manipulation in Python.

In this section, you'll explore the boolean data type and learn how it is used
to develop programs that react to certain conditions.

In this section, you will continue learning about data types and discover
how to organize various attributes in a single variable using lists, tuples, and dictionaries.

In this section, you'll learn how to create loops in Python — an essential skill
for iterating through lists, tuples, and dictionaries.

To conclude this introductory course, you will explore some built-in
functions and then begin to develop your own!

Challenge: Product Management Capstone

Scenario

Output Requirements

解答