1 files changed, 40 insertions, 0 deletions
diff --git a/prolog/problems/lists/rev_2/common.py b/prolog/problems/lists/rev_2/common.py
index ba72492..117049a 100644
--- a/prolog/problems/lists/rev_2/common.py
+++ b/prolog/problems/lists/rev_2/common.py
@@ -1,5 +1,9 @@
 # coding=utf-8
 
+from operator import itemgetter
+import prolog.engine
+import server.problems
+
 id = 111
 number = 18
 visible = True
@@ -14,3 +18,39 @@ rev([H|T], R):-
   rev(T, R1),
   conc111(R1, [H], R).
 '''
+
+test_cases = [
+    ('rev([], X)',
+        [{'X': '[]'}]),
+    ('rev([s, k, c, d, d], X)',
+        [{'X': '[d, d, c, k, s]'}]),
+    ('rev(X, [s, k, c, d, d])',
+        [{'X': '[d, d, c, k, s]'}]),
+]
+
+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 []