add testing dependency

setup.py

@@ -19,7 +19,7 @@
 
 from setuptools import setup, find_packages
 
-tests_require = ["pytest"]
+tests_require = ["pytest", "pytest-cov"]
 
 
 setup(

tests/test_basket.py

@@ -25,6 +25,7 @@ def test_pure_smoothie_types():
 	result = pure_smoothie(apple='apple', orange='orange')
 	assert result == 'appleorange'
 
+
 def test_raises_exception():
 	with pytest.raises(TypeError):
 		pure_smoothie(apple='apple', orange=1)