[Python] 用 Pytest 來做 Unit Test

什麼是Pytest?

來寫測試吧!

• 先用pip安裝pytest:

pip install pytest

• 測試專案 - Folder Structure [Link]

pytest-demo
    │  README.md
    │
    ├─libs
    │      module.py
    │      __init__.py
    │
    └─tests
           test_module.py

• libs\module.py

• tests\test_module.py

我們將驗證 Module.get_true() 的回傳值為True，而 Module.get_false() 回傳值為 False

pytest-demo> pytest
==================== test session starts ====================
platform win32 -- Python 3.6.2, pytest-5.0.1, py-1.8.0, pluggy-0.12.0
rootdir: ..\pytest-demo
collected 2 items
tests\test_module.py ..     [100%]
==================== 2 passed in 0.03 seconds ====================

測試成功的執行了! 但...我想看更詳細的訊息怎麼辦?
使用 pytest -v 或是 pytest --verbose 會得到以下結果~~~~

\pytest-demo> pytest -v
==================== test session starts ==================== platform win32 -- Python 3.6.2, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- ..\programs\python\python36-32\python.exe
cachedir: .pytest_cache
rootdir: ..\pytest-demo
collected 2 items
tests/test_module.py::test_get_true_func PASSED [ 50%] tests/test_module.py::test_get_false_func PASSED [100%]
==================== 2 passed in 0.03 seconds ====================

太神啦! 簡單快速地完成了! 
但我們更改一下 get_true() 的回傳值為 False 來產生測試失敗的狀況:

\pytest-demo> pytest -v
==================== test session starts ====================
platform win32 -- Python 3.6.2, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- ..\programs\python\python36-32\python.exe
cachedir: .pytest_cache
rootdir: ..\pytest-demo
collected 2 items
tests/test_module.py::test_get_true_func FAILED [ 50%] tests/test_module.py::test_get_false_func PASSED [100%]
==================== FAILURES ==================== ____________________________________________________________ test_get_true_func _____________________________________________________________
def test_get_true_func():
>       assert Module.get_true() is True
E       assert False is True
E        +  where False = <function Module.get_true at 0x036A0930>()
E        +    where <function Module.get_true at 0x036A0930> = Module.get_true
tests\test_module.py:5: AssertionError
==================== 1 failed, 1 passed in 0.07 seconds ====================

在 Windows PowerShell Console 下會有顏色可以很簡單的區分 PASS or FAIL

參考資料: