代码覆盖集成进flask-script的test命令中。为什么要写的这么麻烦，用到环境变量，直接写进test函数里不行吗？这个FLASK_COVERAGE环境变量如果自已设定在命令行环境里，那不是运行其他脚本命令（如：python manage.py shell, python manage.py db upgrade）也要开启coverage引擎？
下面是Flask Web Development书中第十五章 测试 中的代码

manage.py： 覆盖检测

#!/usr/bin/env python import os COV = None if os.environ.get('FLASK_COVERAGE'): import coverage COV = coverage.coverage(branch=True, include='app/*') COV.start() # ... @manager.command def test(coverage=False): """Run the unit tests.""" if coverage and not os.environ.get('FLASK_COVERAGE'): import sys os.environ['FLASK_COVERAGE'] = '1' os.execvp(sys.executable, [sys.executable] + sys.argv) import unittest tests = unittest.TestLoader().discover('tests') unittest.TextTestRunner(verbosity=2).run(tests) if COV: COV.stop() COV.save() print('Coverage Summary:') COV.report() basedir = os.path.abspath(os.path.dirname(__file__)) covdir = os.path.join(basedir, 'tmp/coverage') COV.html_report(directory=covdir) print('HTML version: file://%s/index.html' % covdir) COV.erase() # ...