Add even number function and its corresponding unit to main

.vscode/settings.json

@@ -113,5 +113,8 @@
   },
 
   // Enable/disable update table of contents on save
-  "markdown.extension.toc.updateOnSave": false
+  "markdown.extension.toc.updateOnSave": false,
+  "[python]": {
+    "editor.defaultFormatter": "ms-python.black-formatter"
+  }
 }

solutions/is_even.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Created on XX XX XX
+
+A module for checking to see if an integer is even.
+
+@author: Luyando .E. Chitindi
+"""
+
+
+def is_even(number: int) -> bool:
+    """
+    This checks if an integer is even.
+
+    Parameters:
+    number: int, the number to check
+
+    Returns -> bool:
+        True if the number is even, false otherwise.
+
+    Raises:
+        AssertionError: if the input is not an integer
+
+    Example:
+    >>> is_even(4)
+    True
+    >>> is_even(3)
+    False
+    >>> is_even(0)
+    True
+     >>> is_even("hello")
+    Traceback (most recent call last):
+        ...
+    AssertionError: Input must be an integer.
+    """
+    assert isinstance(number, int), "Input must be an integer"
+    if number % 2 == 0:
+        return True
+    return False

solutions/tests/test_is_even.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+import unittest
+from solutions.is_even import is_even
+
+
+class TestIsEven(unittest.TestCase):
+    """Test the is_even function"""
+
+    def test_even_number(self):
+        """It should evaluate 4 to true"""
+        actual = is_even(4)
+        expected = True
+        self.assertEqual(actual, expected)
+
+    def test_odd_number(self):
+        """It should evaluate 3 to False"""
+        actual = is_even(3)
+        expected = False
+        self.assertEqual(actual, expected)
+
+    def test_zero(self):
+        """It should evaluate 0 to True"""
+        actual = is_even(0)
+        expected = True
+        self.assertEqual(actual, expected)
+
+    def test_negative_even_number(self):
+        """It should evaluate -2 to True"""
+        actual = is_even(-2)
+        expected = True
+        self.assertEqual(actual, expected)
+
+    def test_negative_odd_number(self):
+        """It should evaluate -3 to False"""
+        actual = is_even(-3)
+        expected = False
+        self.assertEqual(actual, expected)
+
+    def test_non_integer_input(self):
+        """It should raise an assertion error if the argument is not an integer"""
+        with self.assertRaises(AssertionError):
+            is_even(3.5)
+
+        with self.assertRaises(AssertionError):
+            is_even("string")
+
+    def test_less_than_0(self):
+        """It should raise an assertion error if the argument is less than 0"""
+        with self.assertRaises(AssertionError):
+            is_even(-2.5)
+
+
+if __name__ == "__main__":
+    unittest.main()