Pep8 fixes and changes to NaN tests

common/lib/capa/capa/responsetypes.py

@@ -2,7 +2,8 @@
 # File:   courseware/capa/responsetypes.py
 #
 '''
-Problem response evaluation.  Handles checking of student responses, of a variety of types.
+Problem response evaluation.  Handles checking of student responses,
+of a variety of types.
 
 Used by capa_problem.py
 '''

common/lib/capa/capa/tests/test_responsetypes.py

@@ -442,7 +442,7 @@ class FormulaResponseTest(ResponseTest):
         # This resolves a bug where a problem with relative tolerance would
         # pass with any arbitrarily large student answer.
 
-        sample_dict = {'x' : (1,2)}
+        sample_dict = {'x': (1, 2)}
 
         # Test problem
         problem = self.build_problem(sample_dict=sample_dict,
@@ -457,7 +457,7 @@ class FormulaResponseTest(ResponseTest):
         # attempt to produce a value which causes the student's answer to be
         # evaluated to nan. See if this is resolved correctly.
 
-        sample_dict = {'x' : (1,2)}
+        sample_dict = {'x': (1, 2)}
 
         # Test problem
         problem = self.build_problem(sample_dict=sample_dict,
@@ -465,7 +465,11 @@ class FormulaResponseTest(ResponseTest):
                                      tolerance="1%",
                                      answer="x")
         # Expect an incorrect answer (+ nan) to be marked incorrect
-        input_formula = "10*x + 0*1e999" # right now this evaluates to 'nan' for a given x
+        # right now this evaluates to 'nan' for a given x (Python implementation-dependent)
+        input_formula = "10*x + 0*1e999"
+        self.assert_grade(problem, input_formula, "incorrect")
+        # Expect an correct answer (+ nan) to be marked incorrect
+        input_formula = "x + 0*1e999"
         self.assert_grade(problem, input_formula, "incorrect")
 
 
@@ -763,7 +767,8 @@ class NumericalResponseTest(ResponseTest):
                                      answer=4,
                                      tolerance="10%")
         correct_responses = []
-        incorrect_responses = ["0*1e999"] # right now this evaluates to 'nan' for a given x
+        # right now these evaluate to 'nan'
+        incorrect_responses = ["0*1e999", "4 + 0*1e999"]
         self.assert_multiple_grade(problem, correct_responses, incorrect_responses)
 
     def test_grade_with_script(self):

common/lib/capa/capa/util.py

@@ -23,10 +23,12 @@ def compare_with_tolerance(v1, v2, tol):
         tolerance = evaluator(dict(), dict(), tol)
 
     if isinf(v1) or isinf(v2):
-        return v1 == v2 # because the other numerical comparison does not work with infinities
+        # because the other numerical comparison does not work with infinities
+        return v1 == v2
     else:
         return abs(v1 - v2) <= tolerance
 
+
 def contextualize_text(text, context):  # private
     ''' Takes a string with variables. E.g. $a+$b.
     Does a substitution of those variables from the context '''
@@ -55,7 +57,8 @@ def convert_files_to_filenames(answers):
     new_answers = dict()
     for answer_id in answers.keys():
         answer = answers[answer_id]
-        if is_list_of_files(answer):   # Files are stored as a list, even if one file
+        # Files are stored as a list, even if one file
+        if is_list_of_files(answer):
             new_answers[answer_id] = [f.name for f in answer]
         else:
             new_answers[answer_id] = answers[answer_id]