Merge pull request #96 from ankitjavalkar/code-eval-refactor-clean2

Code evaluator refactor

1 files changed, 58 insertions, 0 deletions

diff --git a/yaksh/python_stdout_evaluator.py b/yaksh/python_stdout_evaluator.py
new file mode 100644
index 0000000..6606581
--- /dev/null
+++ b/yaksh/python_stdout_evaluator.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+import sys
+import traceback
+import os
+from os.path import join
+import importlib
+from contextlib import contextmanager
+
+# local imports
+from code_evaluator import CodeEvaluator
+
+
+@contextmanager
+def redirect_stdout():
+    from StringIO import StringIO
+    new_target = StringIO()
+
+    old_target, sys.stdout = sys.stdout, new_target # replace sys.stdout
+    try:
+        yield new_target # run some code with the replaced stdout
+    finally:
+        sys.stdout = old_target # restore to the previous value
+
+
+class PythonStdoutEvaluator(CodeEvaluator):
+    """Tests the Python code obtained from Code Server"""
+
+    def compile_code(self, user_answer, expected_output):
+        if hasattr(self, 'output_value'):
+            return None
+        else:
+            submitted = compile(user_answer, '<string>', mode='exec')
+            with redirect_stdout() as output_buffer:
+                exec_scope = {}
+                exec submitted in exec_scope
+            self.output_value = output_buffer.getvalue()
+            return self.output_value
+
+    def check_code(self, user_answer, expected_output):
+        success = False
+
+        tb = None
+        if expected_output in user_answer:
+            success = False
+            err = ("Incorrect Answer: Please avoid "
+                "printing the expected output directly"
+            )
+        elif self.output_value == expected_output:
+            success = True
+            err = "Correct answer"
+
+        else:
+            success = False
+            err = "Incorrect Answer"
+
+        del tb
+        return success, err
+