Test in python

Difference between unittest.TestLoader(), unittest.FunctionTestCase(), unittest.TestSuite()

unittest.TestLoader() is a class in the unittest module that provides methods for loading tests from different sources. It allows you to discover and load tests from modules, classes, or other test suites.

unittest.FunctionTestCase() is a class in the unittest module that represents a test case created from a single test function. It allows you to directly create a test case from a function without having to define a separate test class.

unittest.TestSuite() is a class in the unittest module that represents a collection of test cases or other test suites. It allows you to group multiple test cases or test suites together to form a larger suite.

Here's a breakdown of the differences between these three:

1. unittest.TestLoader():

   • It is used to load tests from different sources such as modules, classes, or other test suites.

   • It provides methods like loadTestsFromModule(), loadTestsFromTestCase(), and loadTestsFromName() to discover and load tests.

   • It is useful when you want to dynamically discover and load tests from various sources.

2. unittest.FunctionTestCase():

   • It is used to create a test case directly from a single test function.

   • It allows you to define a test case without creating a separate test class.

   • It is useful when you have a small number of individual test functions that don't require additional setup or customization.

3. unittest.TestSuite():

   • It represents a collection of test cases or other test suites.

   • It allows you to group multiple test cases or test suites together.

   • It provides methods like addTest(), addTests(), and addTestSuite() to add individual test cases or other test suites.

   • It is useful when you want to organize your tests into a hierarchical structure or combine multiple test cases or test suites.

In summary, unittest.TestLoader() is used to load tests from various sources, unittest.FunctionTestCase() is used to create a test case from a single function, and unittest.TestSuite() is used to group and organize multiple test cases or test suites.

self in unittest

class TestBase_instantiation(unittest.TestCase): 
"""Unittests for testing instantiation of the Base class."""
    def test_no_arg(self):
        b1 = Base()
        b2 = Base() 
        self.assertEqual(b1.id, b2.id - 1)

In test cases written using certain testing frameworks, such as the popular unittest framework in Python, the self parameter is used to represent the instance of the test case class. It allows you to access the attributes and methods of the test case class within the test methods.

In the code snippet above, the test case is defined as a method within a class. The self parameter refers to the instance of that test case class. By convention, the first parameter of instance methods in Python is named self.

In the context of test cases, self.assertEqual() is used to assert that two values are equal. The self parameter provides access to this assertion method as well as any other attributes or methods defined within the test case class.