Adding exception handler

Author: krsm

Unitests/pystest_stdy/test_capitalize.py

@@ -14,3 +14,10 @@ def test_capitalize_string():
     c = capitalize.capitalize_string('pytest')
     assert c == 'Pytest'
 
+
+# custom exception
+def test_raises_exception_string_argument():
+    # pytest.raises will raise a TypeError in case
+    # the argument passed is not a string
+    with pytest.raises(TypeError):
+        capitalize.capitalize_string(10)