Assert with the assert statement
Assertions about expected exceptions
Assertions about expected warnings
Making use of context-sensitive comparisons
Defining your own explanation for failed assertions
Assertion introspection details
Assertion rewriting caches files on disk
Pytest使用Python内置的assert的方法，并可以报告常见表达式的值。
如果要判断预期的异常，可以使用pytest.raises()，对于预期的警告，可以使用pyesy.warns