Add error codes to output for easier grader debugging

Author: sarcb

prework.py

@@ -89,9 +89,8 @@ def check_file(filename, correct_hash=None, different_hash=None, correct_perms=N
 
 def is_writable(filename):
     """Check if the given file has any write permissions"""
-    with open(filename, 'rb') as target_file:
-        new_perms = oct(os.stat(filename).st_mode)[-3:]
-        return any([i in "2367" for i in new_perms])
+    new_perms = oct(os.stat(filename).st_mode)[-3:]
+    return any([i in "2367" for i in new_perms])
 
 def check_challenge_1():
     print("### Challenge 1 ###\n")
@@ -115,7 +114,7 @@ def check_challenge_1():
         print(f"\tYour permissions:\tpermanent.txt ({oct(os.stat('permanent.txt').st_mode)[-3:]})\n")
         return False
     else:
-        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_1 command modifies the file's content, but not its' permissions.\n")
+        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_1 command modifies the file's content, but not its' permissions. Error code: {result}\n")
         return False
 
 
@@ -143,7 +142,7 @@ def check_challenge_2():
         print(f"🚧 Your command ran, but it seems like you accidentally modified the contents of permanent.txt.  Please check your command and try again.\n")
         return False
     else:
-        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_2 command modifies the file's permissions, but not its' content.\n")
+        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_2 command modifies the file's permissions, but not its' content. Error code: {result}\n")
         return False
 
 def check_challenge_3():
@@ -159,7 +158,7 @@ def check_challenge_3():
     if result1 == 0:
         print(f"Done.")
     else:
-        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_3 command does not modify the original random.txt file.")
+        print("⛔ Sorry, that's not the right answer. Please make sure your challenge_3 command does not modify the original random.txt file. Error code: {result1}")
         return False
 
     # Check if copy.txt has been created
@@ -175,7 +174,7 @@ def check_challenge_3():
             print(f"Your command was:\n\t> {chal.read()}\n")
         return True
     else:
-        print(f"🚧 You're making progress!  Your command creates copy.txt, but its contents do not match random.txt. Please check your command and try again.\n")
+        print(f"🚧 You're making progress!  Your command creates copy.txt, but its contents do not match random.txt. Please check your command and try again.  Error code: {result2}\n")
         return False
 
 dramatic_print([f"Validating scripts.", ".", ". "])