src/fancymath/math.py

@@ -15,6 +15,14 @@ def fact(n: int) -> int:
         return n * fact(n - 1)
 
 
+def is_even(x):
+    return x % 2 == 0
+
+
+def is_odd(x):
+    return x % 2 == 1
+
+
 if __name__ == '__main__':
     n = 5
     assert fact(n) == 120

src/fancymath/vector.py

@@ -30,6 +30,20 @@ class Vector(object):
         s = "Vector(x=%s, y=%s, z=%s)" % (self.x, self.y, self.z)
         return s
 
+    def __add__(self, other):
+        x = self.x + other.x
+        y = self.y + other.y
+        z = self.z + other.z
+        return self.__class__(x, y, z)
+
+    def __mul__(self, other):
+        if not isinstance(other, Vector):
+            return NotImplemented
+        x = self.y * other.z - self.z * other.y
+        y = self.z * other.x - self.x * other.z
+        z = self.x * other.y - self.y * other.x
+        return self.__class__(x, y, z)
+
 
 if __name__ == "__main__":
     v1 = Vector(3, 4, 0)

test/test_math.py

@@ -0,0 +1,25 @@
+import unittest
+
+from fancymath.math import is_even, is_odd
+
+
+class TestMath(unittest.TestCase):
+    def test_is_even(self):
+        "Test the is_even function"
+        self.assertTrue(is_even(2))
+        self.assertTrue(is_even(-4))
+        self.assertTrue(is_even(0))
+        self.assertFalse(is_even(1))
+        self.assertFalse(is_even(2.5))
+
+    def test_is_odd(self):
+        "Test the is_odd function"
+        self.assertTrue(is_odd(3))
+        self.assertTrue(is_odd(-5))
+        self.assertFalse(is_odd(0))
+        self.assertFalse(is_odd(2))
+        self.assertFalse(is_odd(2.5))
+
+
+if __name__ == "__main__":
+    unittest.main()

test/test_vector.py

@@ -0,0 +1,59 @@
+import unittest
+
+from fancymath.vector import Vector
+
+
+class TestVector(unittest.TestCase):
+    def test_cross_product(self):
+        # Dictionary of (v1, v2): v3
+        values = {
+            (Vector(1, 2, 3), Vector(3, 2, 1)): Vector(-4, 8, -4),
+            (Vector(0, 0, 0), Vector(1, 2, 3)): Vector(0, 0, 0),
+            (Vector(1, 0, 0), Vector(1, 0, 0)): Vector(0, 0, 0),
+        }
+
+        for inputs, expected in values.items():
+            v1, v2 = inputs
+            with self.subTest(v1=v1, v2=v2):
+                v3 = v1 * v2
+
+                self.assertIsInstance(v3, Vector)
+                self.assertEqual(v3.x, expected.x)
+                self.assertEqual(v3.y, expected.y)
+                self.assertEqual(v3.z, expected.z)
+
+    def test_cross_product_failure(self):
+        v1 = Vector(1, 2, 3)
+        v2 = (3, 2, 1)
+
+        with self.assertRaises(TypeError):
+            v1 * v2
+
+
+    def test_add_vector(self):
+        v1 = Vector(1, 2, 3)
+        v2 = Vector(-3, -2, -1)
+        v3 = v1 + v2
+        self.assertIsInstance(v3, Vector)
+        self.assertEqual(v3.x, v1.x + v2.x)
+
+    def test_abs(self):
+        v1 = Vector(0, 0, 0)
+        v2 = Vector(1, 2, 2)
+        v3 = Vector(1, -2, 2)
+        self.assertEqual(v1.abs(), 0)
+        self.assertEqual(v2.abs(), 3)
+        self.assertEqual(v2.abs(), v3.abs())
+
+    def test_dot_failure(self):
+        with self.assertRaises(ValueError):
+            v1 = Vector(1, 2, 3)
+            v1.dot(3)
+
+    def test_dot_product(self):
+        v1 = Vector(1, 2, 3)
+        v2 = Vector(-3, -2, -1)
+        v3 = v1.dot(v2)
+        self.assertEqual(v3,v1.x * v2.x + v1.y * v2.y + v1.z * v2.z)
+        vzero = Vector(0, 0, 0)
+        self.assertEqual(v1.dot(vzero),0)