{"id":3643,"date":"2022-07-04T04:56:30","date_gmt":"2022-07-04T04:56:30","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=3643"},"modified":"2022-07-09T07:26:18","modified_gmt":"2022-07-09T07:26:18","slug":"python-run-unittest","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-unit-testing\/python-run-unittest\/","title":{"rendered":"Organizing Code & Running unittest"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn how to organize the test code and how to use the various commands to run unit tests.<\/p>\n\n\n\n

Organizing code #<\/a><\/h2>\n\n\n\n

If you have a few modules<\/a>, you can create test modules and place them within the same directory. <\/p>\n\n\n\n

In practice, you may have many modules organized into packages<\/a>. Therefore, it’s important to keep the development code and test code more organized.<\/p>\n\n\n\n

It’s a good practice to keep the development code and the test code in separate directories. And you should place the test code in a directory called test<\/code> to make it obvious.<\/p>\n\n\n\n

For demonstration purposes, we’ll create a sample project with the following structure:<\/p>\n\n\n

D:\\python-unit-testing\n\u251c\u2500\u2500 shapes\n|  \u251c\u2500\u2500 circle.py\n|  \u251c\u2500\u2500 shape.py\n|  \u2514\u2500\u2500 square.py\n\u2514\u2500\u2500 test\n   \u251c\u2500\u2500 test_circle.py\n   \u251c\u2500\u2500 test_square.py\n   \u2514\u2500\u2500 __init__.py<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
First, create the shapes<\/code> and test<\/code> directories in the project folder (python-unit-testing<\/code>).<\/p>\n\n\n\n
Second, create three modules shape.py<\/code>, circle.py<\/code>, and square.py<\/code> modules and place them in the shapes<\/code> directory.<\/p>\n\n\n\n
shape.py<\/p>\n\n\n
from<\/span> abc import<\/span> ABC, abstractmethod\n\n\nclass<\/span> Shape<\/span>(ABC)<\/span>:<\/span>\n    @abstractmethod<\/span>\n    def<\/span> area<\/span>()<\/span> -> float:<\/span>\n        pass<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
circle.py<\/p>\n\n\n
import<\/span> math\nfrom<\/span> .shape import<\/span> Shape\n\n\nclass<\/span> Circle<\/span>(Shape)<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, radius: float)<\/span> -> None<\/span>:<\/span>\n        if<\/span> radius < 0<\/span>:\n            raise<\/span> ValueError('The radius cannot be negative'<\/span>)\n\n        self._radius = radius\n\n    def<\/span> area<\/span>(self)<\/span> -> float:<\/span>\n        return<\/span> math.pi * math.pow(self._radius, 2<\/span>)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The Circle<\/code> class also inherits from the Shape<\/code> class. It implements the area()<\/code> method that returns the area of the circle. <\/p>\n\n\n\n
square.py<\/p>\n\n\n
import<\/span> math\nfrom<\/span> .shape import<\/span> Shape\n\n\nclass<\/span> Square<\/span>(Shape)<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, length: float)<\/span> -> None<\/span>:<\/span>\n        if<\/span> length < 0<\/span>:\n            raise<\/span> ValueError('The length cannot be negative'<\/span>)\n        self._length = length\n\n    def<\/span> area<\/span>(self)<\/span> -> float:<\/span>\n        return<\/span> math.pow(self._length, 2<\/span>)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Like the Circle<\/code> class, the Square<\/code> class has the area()<\/code> method that returns the area of the square.<\/p>\n\n\n\n
Third, create the test_circle.py<\/code> and test_square.py<\/code> test modules and place them in the test<\/code> folder:<\/p>\n\n\n\n
test_circle.py<\/p>\n\n\n
import<\/span> unittest\nimport<\/span> math\n\nfrom<\/span> shapes.circle import<\/span> Circle\nfrom<\/span> shapes.shape import<\/span> Shape\n\n\nclass<\/span> TestCircle<\/span>(unittest.TestCase)<\/span>:<\/span>\n    def<\/span> test_circle_instance_of_shape<\/span>(self)<\/span>:<\/span>\n        circle = Circle(10<\/span>)\n        self.assertIsInstance(circle, Shape)\n\n    def<\/span> test_create_circle_negative_radius<\/span>(self)<\/span>:<\/span>\n        with<\/span> self.assertRaises(ValueError):\n            circle = Circle(-1<\/span>)\n\n    def<\/span> test_area<\/span>(self)<\/span>:<\/span>\n        circle = Circle(2.5<\/span>)\n        self.assertAlmostEqual(circle.area(), math.pi * 2.5<\/span>*2.5<\/span>)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The test_circle<\/code> module uses the Circle<\/code> and Shape<\/code> from the circle<\/code> and shape<\/code> test modules in the shapes<\/code> package.<\/p>\n\n\n\n
test_square.py<\/p>\n\n\n
import<\/span> unittest\n\nfrom<\/span> shapes.square import<\/span> Square\nfrom<\/span> shapes.shape import<\/span> Shape\n\n\nclass<\/span> TestSquare<\/span>(unittest.TestCase)<\/span>:<\/span>\n\n    def<\/span> test_create_square_negative_length<\/span>(self)<\/span>:<\/span>\n        with<\/span> self.assertRaises(ValueError):\n            square = Square(-1<\/span>)\n\n    def<\/span> test_square_instance_of_shape<\/span>(self)<\/span>:<\/span>\n        square = Square(10<\/span>)\n        self.assertIsInstance(square, Shape)\n\n    def<\/span> test_area<\/span>(self)<\/span>:<\/span>\n        square = Square(10<\/span>)\n        area = square.area()\n        self.assertEqual(area, 100<\/span>)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The test_square<\/code> module uses the Square<\/code> and Shape<\/code> classes from the square<\/code> and shape<\/code> modules in the shapes<\/code> package.<\/p>\n\n\n\n
It’s important to create an __init__.py<\/code> file and place it in the test<\/code> folder. Otherwise, commands in the following section won’t work as expected.<\/p>\n\n\n\n
Running unit tests #<\/a><\/h2>\n\n\n\n
The unittest<\/a> module provides you with many ways to run unit tests.<\/p>\n\n\n\n
1) Running all tests #<\/a><\/h3>\n\n\n\n
To run all tests in the test<\/code> directory, you execute the following command from the project directory folder (python-unit-testing<\/code>):<\/p>\n\n\n
python -m unittest discover -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The discover<\/code> is a subcommand that finds all the tests in the project.<\/p>\n\n\n\n
Output:<\/p>\n\n\n
test_area (test_circle.TestCircle) ... ok\ntest_circle_instance_of_shape (test_circle.TestCircle) ... ok\ntest_create_circle_negative_radius (test_circle.TestCircle) ... ok\ntest_area (test_square.TestSquare) ... ok\ntest_create_square_negative_length (test_square.TestSquare) ... ok\ntest_square_instance_of_shape (test_square.TestSquare) ... ok\n\n----------------------------------------------------------------------\nRan 6<\/span> tests in<\/span> 0.002<\/span>s\n\nOK<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
2) Running a single test module #<\/a><\/h3>\n\n\n\n
To run a single test module, you use the following command:<\/p>\n\n\n
python -m unittest test_package.test_module -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following execute all tests in the test_circle<\/code> module of the test<\/code> package:<\/p>\n\n\n
python -m unittest test.test_circle -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
test_area (test.test_circle.TestCircle) ... ok\ntest_circle_instance_of_shape (test.test_circle.TestCircle) ... ok     \ntest_create_circle_negative_radius (test.test_circle.TestCircle) ... ok\n\n---------------------------------------------------------------------- \nRan 3<\/span> tests in<\/span> 0.000<\/span>s\n\nOK<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
3) Running a single test class #<\/a><\/h3>\n\n\n\n
A test module may have multiple classes. To run a single test class in a test module, you use the following command:<\/p>\n\n\n
python -m unittest test_package.test_module.TestClass -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following command tests the TestSquare<\/code> class from the test_square<\/code> module of the test package:<\/p>\n\n\n
python -m unittest test.test_circle.TestCircle -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
test_area (test.test_square.TestSquare) ... ok\ntest_create_square_negative_length (test.test_square.TestSquare) ... ok\ntest_square_instance_of_shape (test.test_square.TestSquare) ... ok\n\n----------------------------------------------------------------------\nRan 3<\/span> tests in<\/span> 0.001<\/span>s\n\nOK<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
4) Running a single test method #<\/a><\/h3>\n\n\n\n
To run a single test method of a test class, you use the following command:<\/p>\n\n\n
python -m unittest test_package.test_module.TestClass.test_method -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
For example, the following command tests the test_area()<\/code> method of the TestCircle<\/code> class:<\/p>\n\n\n
python -m unittest test.test_circle.TestCircle.test_area -v<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
test_area (test.test_circle.TestCircle) ... ok\n\n----------------------------------------------------------------------\nRan 1<\/span> test in<\/span> 0.001<\/span>s\n\nOK<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
  • Place the development code and test code in separate directories. It’s a good practice to store the test code in the test directory.<\/li>
  • Use the command python -m unittest discover -v<\/code> to discover and execute all the tests.<\/li>
  • Use the command python -m unittest test_package.test_module -v<\/code> to run a single test module.<\/li>
  • Use the command python -m unittest test_package.test_module.TestClass -v<\/code> to run a single test class.<\/li>
  • Use the command python -m unittest test_package.test_module.TestClass.test_method<\/code> -v to run a single test method.<\/li><\/ul>\n
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The Shape<\/code> class is an abstract class<\/a> that has the area()<\/code> method. It is the base class of the Circle<\/code> and Square<\/code> class.<\/p>\n\n\n\n