为 nbgrader 中的后续自动评分器测试捕获自动评分答案的输出

Question

我正在尝试使用 nbgrader 自动化 autograding。通常学生在教师使用的 autograded answer 单元格中编写一段代码（如 variable 或 function）（通过参考 variable 或 function) 写入 autograder tests.

但有时来自 autograded answer 单元格的输入代码可能只是一个 print(...) 输出到屏幕的东西（而不是 variable 或 function） .在那种情况下，如何捕获打印输出，以便我们可以在下一个单元格上使用它来写入 autograder tests ？

Answer 1

nbgrader 文档 include an example 演示了如何修补内置函数 print 以便您可以捕获和测试打印输出：

Problem: verify that a function call results in the printing of a certain result
def foo()
    #...
    print('right result')
The test code for this can be written as
from unittest.mock import patch
with patch('__main__.print') as mock_print:
    foo()

mock_print.assert_called_once_with('right_result')
This test passes silently if the print is correct, but if the print is wrong:
def foo()
    #...
    print('wrong result')
an assertion error is raised with output of the form
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
...

AssertionError: Expected call: print('right result')
Actual call: print('wrong result')

为 nbgrader 中的后续自动评分器测试捕获自动评分答案的输出

Capture output of autograded answer for subsequent autograder tests in nbgrader

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