解決 python coverage 產生程式碼測試覆蓋率報告遇到的問題

解決 Python 使用 Coverage.py 產生程式碼測試覆蓋率報告 (coverage report) 遇到的問題

[問題1] coverage: command not found
問題狀況:

$ coverage report -m
/bin/bash: line 73: coverage: command not found

解決方式: 安裝 coverage

$ php install coverage

安裝完可以輸入以下指令，確認已經完成安裝

$ coverage --version
Coverage.py, version 4.5.1 with C extension
Documentation at https://coverage.readthedocs.io

[問題2] No data to report
問題狀況:

# 目錄結構: test/test.test_calc.py
$ python -m unittest test.test_calc

$ coverage report -m
Name Stmts Miss Cover Missing
-------------------------------------
No data to report.

解決方式: 原本 python -m 改成 coverage run -m

$ coverage run -m unittest test.test_calc

[問題3] 執行測試的是 test_calc ，卻出現其他 python 程式的覆蓋率結果
問題狀況:

$ coverage report -m
Name Stmts Miss Cover Missing
-----------------------------------------------------------------------------------------------------------
mylib/__init__.py 2 0 100%
mylib/calc.py 5 0 100%
mylib/another.py 9 5 44% 8-15
test/__init__.py 2 0 100%
test/test_calc.py 16 1 94% 24
test/test_another.py 13 6 54% 7, 10, 13-15, 18

解決方式: 使用 --include 變數，指定要測試的檔案名稱

$ coverage run --include ./mylib/calc.py -m unittest test.test_calc

[問題4] Module xxx was never imported. (module-not-imported)
問題狀況:

$ coverage run -a --source mylib/calc.py test/test_calc.py
Traceback (most recent call last):
File "test/test_calc.py", line 2, in
from mylib.calc import Calculator
ModuleNotFoundError: No module named 'mylib'
Coverage.py warning: Module mylib/calc.py was never imported. (module-not-imported)

解決方式: --source 變數是指定要使用的資料夾、要指定檔案需要改成使用 --include 變數