Python & Moodle Integration via Coderunner

import subprocess, json, sys, re

student_func = """{{ STUDENT_ANSWER | e('py') }}"""

code = student_func

# Require use of NumPy

if "import numpy" not in code and "np." not in code:

    output = "Expected solution using NumPy (e.g., import numpy as np)."

    result = {'got': output, 'fraction': 0}

    print(json.dumps(result))

    sys.exit(0)

# Forbid shortcuts for diagonal matrices

forbidden_snippets = [

    "np.diag",

    "np.eye"

]

for snippet in forbidden_snippets:

    if snippet in code:

        output = (

            f"Forbidden construct detected in solution: '{snippet}'. "

            "You must construct the matrix manually (e.g., with a loop)."

        )

        result = {'got': output, 'fraction': 0}

        print(json.dumps(result))

        sys.exit(0)

# Require at least one for-loop

if "for " not in code:

    output = "Expected solution that uses at least one for-loop to fill the matrix."

    result = {'got': output, 'fraction': 0}

    print(json.dumps(result))

    sys.exit(0)

test_program = """

import numpy as np

{{ STUDENT_ANSWER | e('py') }}

ok = True

if "diagonal_matrix" in globals():

    print("Function diagonal_matrix exists.")

else:

    ok = False

    print("Function diagonal_matrix(n) is not defined.")

def diagonal_matrix_ref(n):

    A = np.zeros((n, n), dtype=int)

    for i in range(n):

        A[i, i] = i + 1

    return A

test_values = [3, 5, 10]

for n in test_values:

    if not ok:

        break

    print(f"\\nTesting n = {n}...")

    try:

        A = diagonal_matrix(n)

    except Exception as e:

        ok = False

        print(f"Error when calling diagonal_matrix({n}): {e}")

        break

    try:

        A_np = np.array(A)

    except Exception as e:

        ok = False

        print(f"Could not convert result of diagonal_matrix({n}) to a NumPy array: {e}")

        break

    A_r = diagonal_matrix_ref(n)

    if A_np.shape == A_r.shape:

        print(f"Shape for n={n} is OK.")

    else:

        ok = False

        print(f"Shape for n={n} incorrect. Expected: {A_r.shape}, got: {A_np.shape}.")

        break

    # Value check

    if np.array_equal(A_np, A_r):

        print(f"Values for n={n} are OK.")

    else:

        ok = False

        print(f"Values for n={n} incorrect.\\nExpected:\\n{A_r}\\nGot:\\n{A_np}")

        break

if ok:

    print("\\nAll good!")

else:

    print("\\nNot all tests have been successful!")

"""

try:

    with open('code.py', 'w') as fout:

        fout.write(test_program)

    output = subprocess.check_output(

        ['python3', 'code.py'],

        stderr=subprocess.STDOUT,

        universal_newlines=True

    )

except subprocess.CalledProcessError as e:

    output = e.output

mark = 1 if "All good!" in output.strip() else 0

result = {'got': output, 'fraction': mark}

print(json.dumps(result))