1 files changed, 21 insertions, 20 deletions
diff --git a/python/problems/introduction/fahrenheit_to_celsius/common.py b/python/problems/introduction/fahrenheit_to_celsius/common.py
index 2e6c9b7..2962c55 100644
--- a/python/problems/introduction/fahrenheit_to_celsius/common.py
+++ b/python/problems/introduction/fahrenheit_to_celsius/common.py
@@ -1,6 +1,7 @@
 # coding=utf-8
 
-from python.util import has_token_sequence
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc
 from server.hints import Hint, HintSequence
 
 id = 180
@@ -46,19 +47,28 @@ def test(python, code):
     outputs = [ans[1] for ans in answers]
 
     n_correct = 0
-    for output, correct in zip(outputs, test_out):
+    tin = None
+    for i, (output, correct) in enumerate(zip(outputs, test_out)):
         if correct in output:
             n_correct += 1
+        else:
+            tin = test_in[i][1]
+            tout = correct
 
     passed = n_correct == len(test_in)
     hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_in)}}]
+    if tin:
+        hints.append({'id': 'problematic_test_case', 'args': {'testin': str(tin), 'testout': str(tout)}})
     return passed, hints
 
 def hint(python, code):
+    tokens = get_tokens(code)
+
     # run one test first to see if there are any exceptions
     test_in = [(None, '212\n')]
-    exc = python(code=code, inputs=test_in, timeout=1.0)[0][3]
-    # have an exception!
+    answer = python(code=code, inputs=test_in, timeout=1.0)
+    exc = answer[0][3]
+    exc_hint = get_exception_desc(answer[0][3])
     if exc:
         if 'NameError' in exc:
             return [{'id':'name_error', 'args': {'message': exc}}]
@@ -68,31 +78,22 @@ def hint(python, code):
             return [{'id':'unsupported_operand', 'args': {'message': exc}}]
         elif 'TypeError' in exc:
             return [{'id':'unsupported_operand', 'args': {'message': exc}}]
-
-
-    # the trick is to decide when to show the plan and when the first hint. 
-    # I implemented a simple idea: show plan, when code contains something from the 
-    # solution, but not input. 
-    if len(code.strip()) < 5 or (not has_token_sequence(code, ['input']) and
-                    (has_token_sequence(code, ['32']) or 
-                     has_token_sequence(code, ['=', '5']) or 
-                     has_token_sequence(code, ['print']))):
-        return [{'id': 'plan'}]
-
+        else:
+            return exc_hint
 
     # if input is not present in code, student needs to learn about input
-    if not has_token_sequence(code, ['input']):
+    if not has_token_sequence(tokens, ['input']):
         return [{'id': 'no_input_call'}]
 
     # if tokens * or / or = are not in code, we have to teach them how to 
     # evaluate expressions.
-    if (not has_token_sequence(code, ['/']) or
-        not has_token_sequence(code, ['*']) or
-        not has_token_sequence(code, ['='])):
+    if (not has_token_sequence(tokens, ['/']) or
+        not has_token_sequence(tokens, ['*']) or
+        not has_token_sequence(tokens, ['='])):
         return [{'id' : 'expressions_python'}]
 
     # student is not using print function
-    if not has_token_sequence(code, ['print']):
+    if not has_token_sequence(tokens, ['print']):
         return [{'id' : 'printing'}]
 
     return None