import unittest
import array
import re

# Helper function to dynamically generate test names and assertions
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)


class TestUserCode(unittest.TestCase):

    def test_transaction_has_slots(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code.Transaction, "__slots__"),
            "The `Transaction` class defines `__slots__`.",
            "Expected `Transaction` to define `__slots__`."
        )

    def test_transaction_slots_correct(self):
        import user_code
        expected = {"transaction_id", "amount", "currency"}
        try:
            actual = set(user_code.Transaction.__slots__)
            condition = actual == expected
            failure_message = f"Expected `__slots__` to contain `{expected}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure_message = "The `Transaction` class does not define `__slots__`."
        _dynamic_test(
            self,
            condition,
            f"The `__slots__` contains the correct attributes: `{expected}`.",
            failure_message
        )

    def test_transaction_no_dict(self):
        import user_code
        transaction = user_code.Transaction(1, 100.0, "USD")
        _dynamic_test(
            self,
            not hasattr(transaction, "__dict__"),
            "The `Transaction` instance has no `__dict__` – `__slots__` is working correctly.",
            "Expected `Transaction` instance to have no `__dict__` when `__slots__` is defined."
        )

    def test_usd_amounts_is_array(self):
        import user_code
        _dynamic_test(
            self,
            isinstance(user_code.usd_amounts, array.array),
            "The `usd_amounts` variable is an `array.array` instance.",
            "Expected `usd_amounts` to be of type `array.array`."
        )

    def test_usd_amounts_type_code(self):
        import user_code
        try:
            condition = user_code.usd_amounts.typecode == "d"
            failure_message = f"Expected type code `'d'`, but got `'{user_code.usd_amounts.typecode}'`."
        except AttributeError:
            condition = False
            failure_message = "The `usd_amounts` variable is not declared."
        _dynamic_test(
            self,
            condition,
            "The `usd_amounts` array uses type code `'d'` (double).",
            failure_message
        )

    def test_usd_amounts_values(self):
        import user_code
        expected = array.array("d", [4500.0, 8900.0, 15000.0])
        try:
            condition = user_code.usd_amounts == expected
            failure_message = f"Expected `usd_amounts` to be `{list(expected)}`, but got `{list(user_code.usd_amounts)}`."
        except AttributeError:
            condition = False
            failure_message = "The `usd_amounts` variable is not declared."
        _dynamic_test(
            self,
            condition,
            f"The `usd_amounts` contains the correct values: `{list(expected)}`.",
            failure_message
        )

    def test_generator_used(self):
        with open("user_code.py", "r") as file:
            source = file.read()
        _dynamic_test(
            self,
            bool(re.search(r"Transaction\s*\(.*\)\s+for\s+", source)),
            "A generator expression is used to create `Transaction` objects.",
            "Expected a generator expression to be used for `transaction_stream`."
        )


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

test_main.py

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Explore the essentials of Python's memory management, including reference counting, garbage collection, and memory allocation strategies.

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Challenge: Memory-Efficient Data Pipeline

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