hex_to_binary challenge

solutions/hex_to_binary.py

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+"""
+This module provides a utility function to convert a hexadecimal string
+to its binary representation.
+
+Functions:
+- hex_to_binary: Converts a hexadecimal string to its binary equivalent.
+
+Author: Marc Darazi
+"""
+
+
+def hex_to_binary(hex_string):
+    """
+    Convert a hexadecimal string to its binary representation.
+
+    Parameters:
+        hex_string (str): A string representing a hexadecimal number.
+        It can include a leading '0x' prefix or not.
+
+    Returns:
+        str: A binary string representation of the given hexadecimal number,
+        with leading zeros preserved.
+
+    Raises:
+        ValueError: If the input string is not a valid hexadecimal number.
+
+    Example:
+        >>> hex_to_binary("1A")
+        '11010'
+        >>> hex_to_binary("0xFF")
+        '11111111'
+        >>> hex_to_binary("0x0")
+        '0'
+    """
+    # Remove '0x' prefix if present
+    if hex_string.startswith("0x"):
+        hex_string = hex_string[2:]
+
+    try:
+        # Convert to integer, then to binary
+        binary_string = bin(int(hex_string, 16))[2:]  # Remove '0b' prefix
+        return binary_string
+    except ValueError:
+        raise ValueError("Invalid hexadecimal string")

solutions/tests/test_hex_to_binary.py

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+"""
+This module provides a utility function to convert a hexadecimal string
+to its binary representation.
+
+Functions:
+- hex_to_binary: Converts a hexadecimal string to its binary equivalent.
+
+Author: Marc Darazi
+"""
+
+import unittest
+from ..hex_to_binary import hex_to_binary
+
+
+class TestHexToBinary(unittest.TestCase):
+    """
+    Unit tests for the hex_to_binary function.
+
+    These tests validate that the hex_to_binary function correctly converts
+    hexadecimal strings to binary strings, handling both cases with and
+    without the '0x' prefix and invalid inputs.
+    """
+
+    def test_valid_hex_without_prefix(self):
+        """
+        Test converting a valid hexadecimal string without the '0x' prefix.
+        """
+        self.assertEqual(hex_to_binary("1A"), "11010")
+
+    def test_valid_hex_with_prefix(self):
+        """
+        Test converting a valid hexadecimal string with the '0x' prefix.
+        """
+        self.assertEqual(hex_to_binary("0xFF"), "11111111")
+
+    def test_single_digit_hex(self):
+        """
+        Test converting a single digit hexadecimal string.
+        """
+        self.assertEqual(hex_to_binary("9"), "1001")
+
+    def test_hex_with_lowercase_letters(self):
+        """
+        Test converting a hexadecimal string with lowercase letters.
+        """
+        self.assertEqual(hex_to_binary("a"), "1010")
+
+    def test_invalid_hex_with_non_hex_characters(self):
+        """
+        Test an invalid hexadecimal string with non-hex characters.
+        """
+        with self.assertRaises(ValueError):
+            hex_to_binary("G1")
+
+    def test_empty_string(self):
+        """
+        Test an empty string as input, which should raise a ValueError.
+        """
+        with self.assertRaises(ValueError):
+            hex_to_binary("")