Gao fushuai of the unit test community, what about the Pytest framework, use case marking and test execution

Posted by CKPD on Fri, 07 Jan 2022 13:29:56 +0100

♥ preface

In the introduction of the last article, we introduced the pre and post methods and fixture mechanism of pytest. This chapter mainly introduces the marking mechanism and use case execution method in pytest. Pytest can pass the data into the test function through the tag, or filter the executed use cases through the tag, and then go directly to the topic.

1, Built in tags in pytest

The use of pytest tag needs to pass pytest mark. In order to deal with various test scenarios, pytest also has many built-in tags.

1.1,pytest. mark. Parameterize: mark of use case parameterization

By parameterizing, you can separate the use case data from the logic code executed by the use case, and automatically generate test cases according to the use cases.

Demo:

@pytest.mark.parametrize('item',[11,22,33,44,55,66])
def test_demo(item)
  assert item > 50

1.2,pytest.mark.skip: skip case execution

Use cases decorated with skip will be skipped unconditionally during execution,

Parameter reason: reason for skipping the test function.

Demo

# Do not write skip reason
@pytest.mark.skip
def test_demo()
  assert item > 50

# Write skip reason
@pytest.mark.skip(reason='No execution required')
def test_demo()
  assert item > 50

1.3,pytest.mark.skipif: skip use cases based on conditions

skipif can decide whether to skip the execution of the use case according to the condition. If the condition is True, the execution of the test function will be skipped.

Parameter: condition - condition to skip

Parameter: reason - reason for skipping

Demo

a = 10
@pytest.mark.skipif(a > 20,reason='If the condition is not established, it will not be implemented')
def test_demo()
  assert item > 50

1.4,pytest.mark.xfail: marks the use case of the expected failure

xfail can mark a test function as a use case for an expected execution failure.

Parameter: condition - condition to mark the test function as xfail (True/False)

Parameter: reason - the reason why the test function is marked as xfail

Parameter: raises - exception type of expected failure

Parameter: run - whether the test function should actually be executed. If False, the function will always xfail and will not be executed.

Parameter: strict -- strict mode (True/False)

Demo

a = 10
@pytest.mark.xfail(a > 20,reason='If the condition is not established, it will not be implemented' raises=AssertionError )
def test_demo()
  assert item > 50

1.5,pytest. mark. Use fixtures: set test fixtures for test classes or modules

The usefixtures tag is generally used to uniformly set test fixtures for the test methods under the test class.

Demo

# All test cases of the TestDome test class execute my_fixture this fixture
@pytest.mark.usefixtures('my_fixture This fixture')
class TestDome:
    # Function case specifies the test fixture
    def test_02(self):
        print('----Test case: test_01------')

    # Function case specifies the test fixture
    def test_03(self):
        print('----Test case: test_02------')

2, Custom tag

Pytest supports passing pytest INI file to register custom tags. To meet the requirements of filtering use cases through tags when executing use cases.,

2.1 registration mark

pytest. The syntax of the INI file registration tag is as follows:

[pytest]

markers =
    Mark 1
    Mark 2

2.2 marking function

Demo:

# Load label before use case: @ pytest mark. Tag name  
@pytest.mark.main
 def test_demo():
    pass

2.3 marking

Demo:

# Method 1: mark the class directly
@pytest.mark.main
class TestClass(object):
    def test_demo1(self):
        assert 10 > 20
  
# Method 2: multiple tags can be added at the same time through the class attribute pytestmark
class TestClass(object):
    pytestmark = [pytest.mark.main, pytest.mark.main]
  
    def test_demo1(self):
        assert 10 > 20

3, Filter case execution by tags

Demo: the existing use cases are as follows:

import pytest

@pytest.mark.yuze
@pytest.mark.musen
def test_01():
    print("Use case 1")

def test_02():
    print("Use case 2")

@pytest.mark.musen
def test_03():
    print("Use case 3")

@pytest.mark.musen
def test_04():
    print("Use case 4")

@pytest.mark.yuze
def test_05():
    print("Use case 5")

@pytest.mark.yuze
def test_06():
    print("Use case 6")

There are 6 test cases in the above Demo, which pass pytest mark. Yuze and pytest mark. Musen has been tagged. Next, let's take a look at how to select use case execution through tags.

3.1. Screening by single marker

Syntax: pytest -m 'tag name'

Demo: pytest -m musen

The results are as follows:

========================== test session starts ==========================
platform win32 -- Python 3.7.3, pytest-5.4.2, py-1.8.0, pluggy-0.13.0
rootdir: C:\project\, inifile: pytest.ini
plugins: allure-pytest-2.8.15, Faker-8.11.0, metadata-1.9.0, parallel-0.0.8, repeat-0.8.0, rerunfailures-9.0, testreport-1.1.2
collected 6 items / 3 deselected / 3 selected                                                                                                               
test_mode.py ...      [100%]
========================== 3 passed, 3 deselected in 0.29s ==========================

You can see that three use cases are executed and three are not selected.

3.2. Select multiple tags at the same time

Syntax: pytest -m "tag 1 or tag 2"

Command: pytest -m "musen ro yuze"

Execute use cases marked by musen or yuze. The results are as follows:

========================== test session starts ==========================
platform win32 -- Python 3.7.3, pytest-5.4.2, py-1.8.0, pluggy-0.13.0
rootdir: C:\project\, inifile: pytest.ini
plugins: allure-pytest-2.8.15, Faker-8.11.0, metadata-1.9.0, parallel-0.0.8, repeat-0.8.0, rerunfailures-9.0, testreport-1.1.2
collected 6 items / 1 deselected / 5 selected                                                                                                               
test_mode.py .....      [100%]
========================== 5 passed, 1 deselected in 0.29s ==========================

As can be seen from the above results, as long as either musen or yuze is added

Syntax: pytest -m "tag 1 and tag 2"

Command: pytest -m "musen and yuze"

Execute the use cases marked simultaneously by musen and yuze. The results are as follows

========================== test session starts ==========================
platform win32 -- Python 3.7.3, pytest-5.4.2, py-1.8.0, pluggy-0.13.0
rootdir: C:\project\, inifile: pytest.ini
plugins: allure-pytest-2.8.15, Faker-8.11.0, metadata-1.9.0, parallel-0.0.8, repeat-0.8.0, rerunfailures-9.0, testreport-1.1.2
collected 6 items / 5 deselected / 1 selected                                                                                                               
test_mode.py .      [100%]
========================== 1 passed, 5 deselected in 0.29s ==========================

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