Test Files

Otter requires OK-formatted tests to check students’ work against. These have a very specific format, described in detail in the OK documentation.

OK Format Caveats

While otter uses OK format, there are a few caveats to the tests when using them with otter.

  • Otter only allows a single suite in each test, although the suite can have any number of cases. This means that test["suite"] should be a list of length 1, whose only element is a dict.
  • Otter has an additional key in the test dict, called hidden. test["hidden"] should evaluate to a boolean. This is used to indicate whether or not the test should be shown on Gradescope when students submit their work. If test["hidden"] is True, then all cases will be shown to students on Gradescope. This is not to be confused with the hidden key of each case, which are ignored by otter.

Sample Test

Here is an annotated sample OK test:

test = {
    "name": "q1",       # name of the test
    "points": 1,        # number of points for the entire suite
    "hidden": False,    # whether the test is hidden on Gradescope
    "suites": [         # list of suites, only 1 suite allowed!
            "cases": [                  # list of test cases
                {                       # each case is a dict
                    "code": r"""        # test, formatted for Python interpreter
                    >>> 1 == 1          # note that in any subsequence line of a multiline
                    True                # statement, the prompt becomes ... (see below)
                    "hidden": False,    # ignored by otter
                    "locked": False,    # ignored by otter
                    "code": r"""
                    >>> for i in range(4):
                    ... 	print(i == 1)
                    "hidden": False,
                    "locked": False,
            "scored": False,            # ignored by otter
            "setup": "",                # ignored by otter
            "teardown": "",             # ignored by otter
            "type": "doctest"           # the type of test; only "doctest" allowed

Writing OK Tests

You can find an online OK test generator that will assist you in generating these test files.