Change error_messages.py, python_assertion_evaluator.py and grader.py

- Pep8 changes
- Show code error message along with test case
- Add nose in python exec scope

3 files changed, 37 insertions, 46 deletions

diff --git a/yaksh/error_messages.py b/yaksh/error_messages.py
index 7ea8618..f2dc7c6 100644
--- a/yaksh/error_messages.py
+++ b/yaksh/error_messages.py
@@ -3,6 +3,7 @@ try:
 except ImportError:
     from itertools import izip_longest as zip_longest
 
+
 def prettify_exceptions(exception, message, traceback=None, testcase=None):
     err = {"type": "assertion",
            "exception": exception,
@@ -13,23 +14,27 @@ def prettify_exceptions(exception, message, traceback=None, testcase=None):
         err["traceback"] = None
 
     if exception == 'AssertionError':
-        value = ("Expected answer from the"  
-                + " test case did not match the output")
-        err["message"] = value
+        value = ("Expected answer from the" +
+                 " test case did not match the output")
+        if message:
+            err["message"] = message
+        else:
+            err["message"] = value
         err["traceback"] = None
-        if testcase:
-            err["test_case"] = testcase
+    err["test_case"] = testcase
     return err
 
+
 def _get_incorrect_user_lines(exp_lines, user_lines):
     err_line_numbers = []
     for line_no, (expected_line, user_line) in \
-     enumerate(zip_longest(exp_lines, user_lines)):
-        if not user_line or not expected_line or \
-         user_line.strip() != expected_line.strip():
+            enumerate(zip_longest(exp_lines, user_lines)):
+        if (not user_line or not expected_line or
+                user_line.strip() != expected_line.strip()):
             err_line_numbers.append(line_no)
     return err_line_numbers
-    
+
+
 def compare_outputs(expected_output, user_output, given_input=None):
     given_lines = user_output.splitlines()
     exp_lines = expected_output.splitlines()
@@ -44,18 +49,17 @@ def compare_outputs(expected_output, user_output, given_input=None):
     msg["error_line_numbers"] = err_line_numbers
     if ng != ne:
         msg["error_msg"] = ("Incorrect Answer: "
-                            + "We had expected {} number of lines. "\
-                                .format(ne)
+                            + "We had expected {} number of lines. ".format(ne)
                             + "We got {} number of lines.".format(ng)
                             )
         return False, msg
     else:
         if err_line_numbers:
             msg["error_msg"] = ("Incorrect Answer: "
-                             + "Line number(s) {0} did not match."
-                                .format(", ".join(map(
-                                  str,[x+1 for x in err_line_numbers]
-                                ))))
+                                + "Line number(s) {0} did not match."
+                                .format(", ".join(
+                                    map(str, [x+1 for x in err_line_numbers])
+                                )))
             return False, msg
         else:
             msg["error_msg"] = "Correct Answer"
diff --git a/yaksh/grader.py b/yaksh/grader.py
index 38cce8d..a721236 100644
--- a/yaksh/grader.py
+++ b/yaksh/grader.py
@@ -1,22 +1,12 @@
 #!/usr/bin/env python
 from __future__ import unicode_literals
 import sys
-import pwd
 import os
-import stat
 import contextlib
-from os.path import isdir, dirname, abspath, join, isfile, exists
+from os.path import dirname, abspath
 import signal
 import traceback
-from multiprocessing import Process, Queue
-import subprocess
-import re
 
-try:
-    from SimpleXMLRPCServer import SimpleXMLRPCServer
-except ImportError:
-    # The above import will not work on Python-3.x.
-    from xmlrpc.server import SimpleXMLRPCServer
 
 # Local imports
 from .settings import SERVER_TIMEOUT
@@ -26,11 +16,13 @@ from .error_messages import prettify_exceptions
 MY_DIR = abspath(dirname(__file__))
 registry = None
 
+
 # Raised when the code times-out.
 # c.f. http://pguides.net/python/timeout-a-function
 class TimeoutException(Exception):
     pass
 
+
 @contextlib.contextmanager
 def change_dir(path):
     cur_dir = abspath(dirname(MY_DIR))
@@ -75,7 +67,6 @@ class Grader(object):
         self.timeout_msg = msg
         self.in_dir = in_dir if in_dir else MY_DIR
 
-
     def evaluate(self, kwargs):
         """Evaluates given code with the test cases based on
         given arguments in test_case_data.
@@ -122,7 +113,6 @@ class Grader(object):
             test_case_instances.append(test_case_instance)
         return test_case_instances
 
-
     def safe_evaluate(self, test_case_instances):
         """
         Handles code evaluation along with compilation, signal handling
@@ -155,20 +145,19 @@ class Grader(object):
                 test_case_instance.teardown()
 
         except TimeoutException:
-            error.append(prettify_exceptions("TimeoutException",
-                                             self.timeout_msg
-                                             )
-                         )
+            error.append(
+                prettify_exceptions("TimeoutException", self.timeout_msg)
+                )
         except Exception:
             exc_type, exc_value, exc_tb = sys.exc_info()
             tb_list = traceback.format_exception(exc_type, exc_value, exc_tb)
             if len(tb_list) > 2:
                 del tb_list[1:3]
-            error.append(prettify_exceptions(exc_type.__name__,
-                                         str(exc_value),
-                                         "".join(tb_list),
-                                         )
-                         )
+            error.append(
+                prettify_exceptions(
+                    exc_type.__name__, str(exc_value), "".join(tb_list)
+                    )
+                )
         finally:
             # Set back any original signal handler.
             set_original_signal_handler(prev_handler)
diff --git a/yaksh/python_assertion_evaluator.py b/yaksh/python_assertion_evaluator.py
index 440f422..8c7d451 100644
--- a/yaksh/python_assertion_evaluator.py
+++ b/yaksh/python_assertion_evaluator.py
@@ -1,10 +1,6 @@
 #!/usr/bin/env python
 import sys
 import traceback
-import os
-import re
-from os.path import join
-import importlib
 
 # Local imports
 from .file_utils import copy_files, delete_files
@@ -43,6 +39,7 @@ class PythonAssertionEvaluator(BaseEvaluator):
             submitted = compile(self.user_answer, '<string>', mode='exec')
             self.exec_scope = {}
             exec(submitted, self.exec_scope)
+            exec("from nose.tools import *", self.exec_scope)
             return self.exec_scope
 
     def check_code(self):
@@ -53,18 +50,19 @@ class PythonAssertionEvaluator(BaseEvaluator):
         --------
         Returns a tuple (success, error, test_case_weight)
 
-        success - Boolean, indicating if code was executed successfully, correctly
+        success - Boolean, indicating if code was executed successfully,
+        correctly
         weight - Float, indicating total weight of all successful test cases
         error - String, error message if success is false
 
-        returns (True, "Correct answer", 1.0) : If the student script passes all
-        test cases/have same output, when compared to the instructor script
+        returns (True, "Correct answer", 1.0) : If the student script passes
+        all test cases/have same output, when compared to the instructor script
 
         returns (False, error_msg, 0.0): If the student script fails a single
         test/have dissimilar output, when compared to the instructor script.
 
-        Returns (False, error_msg, 0.0): If mandatory arguments are not files or if
-        the required permissions are not given to the file(s).
+        Returns (False, error_msg, 0.0): If mandatory arguments are not files
+        or if the required permissions are not given to the file(s).
         """
         success = False
         mark_fraction = 0.0