Question Authors' Forum

Hi Anton

Since my Java's a bit rusty, I'm not sure I fully understand the problem. But the way I deal with issues like this in Python, say when scripting C questions, is firstly to get all the input data - student program, test code, etc - as strings. I like to do that first, to avoid cluttering the rest of the template with ugly Twig syntax. Then I write the student program to a file and try compiling it. If there are any errors, they get displayed and the process is aborted. Otherwise, and if it's not a precheck, I dynamically construct the tester (as a string) from the student program plus all the tests, write the string to a file, and compile and run that.

I'm not sure if it helps, but here's my Python get_test_cases function from one of my standard templates, whereTestCase is a class that wraps the test info. This function gets all the test data into an array of TestCase objects for use within a template grader - for simpler applications all you need is just the array of testcodes, probably.

def get_test_cases():
    """Return an array of Test objects from the template parameter TESTCASES"""
    test_cases = []
{% for TEST in TESTCASES %}
    testcode = """{{ TEST.testcode | e('py') }}\n"""
    stdin = """{{ TEST.stdin | e('py') }}\n"""
    extra = """{{ TEST.extra | e('py') }}\n"""
    expected = """{{ TEST.expected | e('py') }}\n"""
    display = """{{ TEST.display | e('py') }}\n"""
    hiderestiffail = """{{ TEST.hiderestiffail | e('py') }}\n"""
    mark = {{ TEST.mark }}
    useasexamplestring = """{{ TEST.useasexample | e('py')}}"""
    useasexample = useasexamplestring not in ['', '0']  # Tricky! Empty during validation.
    testtype = {{ TEST.testtype }}
    test_cases.append(TestCase(testcode, stdin, extra, expected, display, hiderestiffail, mark, useasexample, testtype))
{% endfor %}
    return test_cases

However, you may think that's too complicated. You ask "Is there something in Twig that would allow me to selectively include student_answer perhaps?". Certainly you could use a Twig if statement that tests the IS_PRECHECK template parameter to conditionally include the test data with the student program. Something like

{% if not IS_PRECHECK %}
{% for TEST in TESTCASES %}
    {
    {{ TEST.testcode }};
    {% if not loop.last %}
    System.out.println(SEPARATOR);
    {% endif %}
    }
{% endfor %}
{% endif %}

I'm not sure if that answers your question or not. Feel free to try again if I've missed the point.

Richard