Can we customise the "output" field's formatting?

[Protofall]

Hello, I'm sorry if this question has an obvious answer, but I was not able to find an answer in the documentation or via my own debugging over the past few days.

I've based my system on this example, the key part is test_generator.py and the assertIn check. My expected output is:

1 2

So this has characters "1", "(space)", "2" and "newline-char" in that order, now if my program has the same output then the test passes and its all good, but my issue is with the fail case outputting. The output field in the JSON results file is set to things like

"Test Failed: '1 2\\n' not found in 'invalid-output' : [msg]\n"

Notice how the first newline char is escaped. This means on the gradescope website it actually outputs \n instead of doing a newline. I can see why this is the default behaviour, for most cases this is preferred, but I'd like to override this formatting and display the output in a more natural way, something like

Test failed:

Expected:
\```
1 2

\```

in user output:
\```
invalid-input
\```

[msg]

The problem is I don't know how and where to override the output string. I think this has nothing to do with the python unit tests/assertIn and instead is a gradescope-utils thing, but I don't know what exactly I'm looking for.

[liamsaliba]

The assertIn function (as well as other assertX functions) has a msg parameter where you can pass in a custom message.

To hide the default message generated by the assertX functions, you can call self.longMessage = False prior to calling the assertX function. I've placed it inside of setUp in my own use.

[Protofall]

Ok, I knew about msg being appended to the default diff message, but I wasn't aware of self.longMessage. I'll try that out and will report back later.

[Protofall]

Yes, that's it! Thank you so much, I never would have found this flag on my own. For anyone whose curious, here's the "prettyAssert" function I made that gives the output I described above:

def prettyAssertIn(self, ex_out, out, bonus_msg):
    bar = "=========="

    msg = "\n\nExpected:\n"
    msg += bar + "\n"
    msg += ex_out
    msg += "\n" + bar
    msg += "\n\nIn user output:\n"
    msg += bar + "\n"
    msg += out
    msg += "\n" + bar + "\n"
    if bonus_msg != None:
        msg += "\n" + bonus_msg + "\n"

    longMessageCopy = self.longMessage
    self.longMessage = False
    self.assertIn(ex_out, out, msg=msg)
    self.longMessage = longMessageCopy