added python stdio evaluator

1 files changed, 68 insertions, 0 deletions

diff --git a/yaksh/python_stdio_evaluator.py b/yaksh/python_stdio_evaluator.py
new file mode 100644
index 0000000..5db80f5
--- /dev/null
+++ b/yaksh/python_stdio_evaluator.py
@@ -0,0 +1,68 @@
+#!/usr/bin/env python
+import sys
+import traceback
+import os
+from os.path import join
+import importlib
+from contextlib import contextmanager
+from ast import literal_eval
+# local imports
+from code_evaluator import CodeEvaluator
+from StringIO import StringIO
+
+
+@contextmanager
+def redirect_stdout():
+    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 PythonStdioEvaluator(CodeEvaluator):
+    """Tests the Python code obtained from Code Server"""
+
+    def compile_code(self, user_answer, expected_input, expected_output):
+        submitted = compile(user_answer, '<string>', mode='exec')
+        if expected_input:
+            input_buffer = StringIO()
+            try:
+                literal_input = literal_eval(expected_input.split("\n"))
+            except ValueError:
+                literal_input = expected_input.split("\n")
+            for inputs in literal_input:
+                input_buffer.write(str(inputs)+'\n')
+            input_buffer.seek(0)
+            sys.stdin = input_buffer
+
+        with redirect_stdout() as output_buffer:
+            exec_scope = {}
+            exec submitted in exec_scope
+        self.output_value = output_buffer.getvalue().rstrip("\n")
+        return self.output_value
+
+    def check_code(self, user_answer, expected_input, 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:\nExpected output - {0}
+                     and your output - {1}"""\
+                  .format(expected_output, self.output_value)
+
+        del tb
+        return success, err