1 files changed, 92 insertions, 0 deletions
diff --git a/yaksh/hook_evaluator.py b/yaksh/hook_evaluator.py
new file mode 100644
index 0000000..5480849
--- /dev/null
+++ b/yaksh/hook_evaluator.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python
+from __future__ import unicode_literals
+import sys
+import traceback
+import os
+from os.path import join
+import importlib
+
+# Local imports
+from .file_utils import copy_files, delete_files
+from .base_evaluator import BaseEvaluator
+from .grader import TimeoutException
+
+
+class HookEvaluator(BaseEvaluator):
+    def __init__(self, metadata, test_case_data):
+        self.exec_scope = None
+        self.files = []
+
+        # Set metadata values
+        self.user_answer = metadata.get('user_answer')
+        self.file_paths = metadata.get('file_paths')
+        self.partial_grading = metadata.get('partial_grading')
+
+        # Set test case data values
+        self.test_case = test_case_data.get('code')
+        self.weight = test_case_data.get('weight')
+
+    def teardown(self):
+        # Delete the created file.
+        if self.files:
+            delete_files(self.files)
+
+    def compile_code(self):
+        if self.file_paths:
+            self.files = copy_files(self.file_paths)
+        if self.exec_scope:
+            return None
+        else:
+            submitted = compile(self.user_answer, '<string>', mode='exec')
+            self.exec_scope = {}
+            exec(submitted, self.exec_scope)
+            return self.exec_scope
+    
+    def check_code(self):
+        """ Function validates user answer by running an assertion based test case
+        against it
+
+        Returns
+        --------
+        Returns a tuple (success, error, test_case_weight)
+
+        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 (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).
+        """
+        success = False
+        mark_fraction = 0.0
+        try:
+            tb = None
+            _tests = compile(self.test_case, '<string>', mode='exec')
+            exec(_tests, globals())
+            success, err, mark_fraction = check_answer(self.user_answer)
+        except AssertionError:
+            type, value, tb = sys.exc_info()
+            info = traceback.extract_tb(tb)
+            fname, lineno, func, text = info[-1]
+            text = str(self.test_case)
+            err = "Expected Test Case:\n{0}\n" \
+                "Error - {1} {2} in: {3}\n".format(
+                    self.test_case,
+                    type.__name__,
+                    str(value),
+                    text
+                    )
+        except TimeoutException:
+            raise
+        except Exception:
+            msg = traceback.format_exc(limit=0)
+            err = "Error in Test case: {0}".format(msg)
+        del tb
+        return success, err, mark_fraction
+ 
+\ No newline at end of file