As Python is a dynamic language, unit testing is not only important for verifying code works as expected, but also needs to cover situations that statically typed languages get for free. So a high level of test coverage is useful to ensure event basic methods are working and even named as expected.<\/p>\n
Let’s create a simply Calculator class which we will then write unit tests for (this is saved in a file named calc.py)<\/p>\n
\r\nclass Calculator:\r\n def add(self, a, b):\r\n return a + b\r\n<\/pre>\nWe can then create a file test_calculator.py and within this we have the following<\/p>\n
\r\nfrom unittest import TestCase\r\nfrom calc import Calculator\r\n\r\n\r\nclass TestCalculator(TestCase):\r\n def test_add(self):\r\n c = Calculator()\r\n self.assertEqual(5, c.add(3, 2))\r\n<\/pre>\nAs you can see, we need to derive our test class from the TestCase class and test methods should use the naming convention test_<\/em> at the start of the test method’s name.<\/p>\n
Note: the class name does not require the Test prefix\/naming convention.<\/em><\/p>\n
Using PyCharm we need to create a new configuration, from the Python tests configuration section. Select nosetests and then name the configuration, something like Calculator Tests.<\/p>\n
Now we can run the tests. If you find nosetest is not installed you can run the Python Console from PyCharm and run the command<\/p>\n
\r\npip install nose\r\n<\/pre>\nsetUp\/tearDown<\/strong><\/p>\n
Like most unit testing frameworks, the TestCase class can use a setUp and\/or tearDown method for setting up the test case context and cleaning up after each test method is run.<\/p>\n
For example<\/p>\n
\r\nclass CalculatorTests(TestCase):\r\n\r\n def setUp(self):\r\n self.c = Calculator()\r\n\r\n def test_add(self):\r\n self.assertEqual(5, self.c.add(3, 2))\r\n\r\n def test_subtract(self):\r\n self.assertEqual(2, self.c.subtract(7, 5))\r\n<\/pre>\nsetUpClass\/tearDownClass<\/strong><\/p>\n
TestCase also includes setUpClass and tearDownClass for setting context for all test methods within a TestCase.<\/p>\n
For example, here’s the previous TestCase but using the setUpClass to create the calculator for all test methods<\/p>\n
\r\nclass CalculatorTests(TestCase):\r\n\r\n @classmethod\r\n def setUpClass(cls):\r\n cls.c = Calculator()\r\n\r\n def test_add(self):\r\n self.assertEqual(5, self.c.add(3, 2))\r\n\r\n def test_subtract(self):\r\n self.assertEqual(2, self.c.subtract(7, 5))\r\n<\/pre>\nNote: the @classmethod is required in this example code or the setUpClass is not treated as a class method as is expected.<\/em><\/p>\n
References<\/strong><\/p>\n
unittest \u2014 Unit testing framework<\/a>
\nCreating and running a Python unit test<\/a> <\/p>\n","protected":false},"excerpt":{"rendered":"As Python is a dynamic language, unit testing is not only important for verifying code works as expected, but also needs to cover situations that statically typed languages get for free. So a high level of test coverage is useful to ensure event basic methods are working and even named as expected. Let’s create a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[195],"tags":[],"class_list":["post-5739","post","type-post","status-publish","format-standard","hentry","category-python"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/posts\/5739","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/comments?post=5739"}],"version-history":[{"count":6,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/posts\/5739\/revisions"}],"predecessor-version":[{"id":5745,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/posts\/5739\/revisions\/5745"}],"wp:attachment":[{"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/media?parent=5739"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/categories?post=5739"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/putridparrot.com\/blog\/wp-json\/wp\/v2\/tags?post=5739"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}