1 files changed, 40 insertions, 0 deletions
diff --git a/prolog/problems/lists/sum_2/common.py b/prolog/problems/lists/sum_2/common.py
index 9c17e9c..2a17157 100644
--- a/prolog/problems/lists/sum_2/common.py
+++ b/prolog/problems/lists/sum_2/common.py
@@ -1,5 +1,9 @@
 # coding=utf-8
 
+from operator import itemgetter
+import prolog.engine
+import server.problems
+
 id = 118
 number = 25
 visible = True
@@ -11,3 +15,39 @@ sum([H|T], Sum) :-
   sum(T, SumT),
   Sum is SumT + H.
 '''
+
+test_cases = [
+    ('sum([], X)',
+        [{'X': '0'}]),
+    ('sum([8, 3, 5, 1], X)',
+        [{'X': '17'}]),
+    ('sum([2, -3, 5, 0], X)',
+        [{'X': '4'}]),
+]
+
+def test(program, solved_problems):
+    code = (program + '\n' +
+            server.problems.solutions_for_problems('prolog', solved_problems))
+
+    n_correct = 0
+    engine_id = None
+    try:
+        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
+        if engine_id is not None and 'error' not in map(itemgetter(0), output):
+            # Engine successfully created, and no syntax error in program.
+            for query, answers in test_cases:
+                # Limit inferences for each solution to curb unbounded recursion.
+                limited = 'call_with_inference_limit(({}), 100000, _)'.format(query)
+                if prolog.engine.check_answers(engine_id, query=limited, answers=answers, timeout=1.0):
+                    n_correct += 1
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
+    passed = n_correct == len(test_cases)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
+    return passed, hints
+
+def hint(program, solved_problems):
+    # TODO
+    return []