Add more exercises

Author: abregman

README.md

@@ -13,6 +13,13 @@
 |--------|--------|------|----|
 | Calculator | [Exercise](exercises/functions/calculator.md) | [Solution](solutions/functions/calculator.md) | |
 
+## Unit Testing
+
+|Name|Objective & Instructions|Solution|Comments|
+|--------|--------|------|----|
+| Calculator Unit Tests | [Exercise](exercises/unit_testing/calculator.md) | [Solution](solutions/unit_testing/calculator.md) | |
+| Fix Calculator Unit Tests | [Exercise](exercises/unit_testing/fix_calculator_tests.md) | | |
+
 ## Exceptions
 
 |Name|Objective & Instructions|Solution|Comments|

exercises/exceptions/divide_by_zero.md

@@ -0,0 +1,22 @@
+# Calculator - Unit Tests
+
+Write unit tests for the following functions
+
+```python
+def add(x, y):
+   """Add numbers"""
+   return x + y
+
+def substract(x, y):
+   """Substract numbers"""
+   return x - y
+
+def multiply(x, y):
+   """Multiply numbers"""
+
+def divide(x, y):
+   """Divide numbers"""
+   if y == 0:
+       raise ValueError('Can not divide by zero!')
+   return x / y
+```

exercises/unit_testing/calculator.md

@@ -0,0 +1,17 @@
+## Fix Calculator Tests
+
+Fix the following Python test file to run successfully the tests
+
+```python
+import unittest
+import calc
+
+class TestCalculator(unittest.TestCase):
+
+def add_test(self):
+    self.assertEqual(calculator.add(1, 1), 2)
+
+
+def test_substract():
+    self.assertEqual(calculator.substract(4, 3), 1)
+```