Prevent replacing disk checkbox FAILED value

* Addresses issue #40

.bin/Scripts/functions/osticket.py

@@ -344,6 +344,38 @@ class osTicket():
 
     return type_str
 
+  def get_flag(self, ticket_id, flag_name):
+    """Get flag in osTicket."""
+    flag_value = None
+    self.connect(silent=True)
+
+    # Bail if disabled
+    if self.disabled:
+      return
+
+    # Build SQL cmd
+    sql_cmd = "SELECT `{column}` FROM `{Name}`.`{Ticket}`".format(
+      column=flag_name,
+      **OSTICKET['Database'],
+      **OSTICKET['Tables'])
+    sql_cmd += "WHERE `{Ticket}`.`ticket_id` = {ticket_id}".format(
+      ticket_id=ticket_id,
+      **OSTICKET['Tables'])
+    sql_cmd +=  ";"
+
+    # Run SQL cmd and get value
+    try:
+      self.db_cursor.execute(sql_cmd)
+      for s in self.db_cursor:
+        flag_value = s[0]
+    except mariadb.errors.Error:
+      # Set self.errors to enable warning line on results screen
+      self.errors = True
+
+    # Done
+    self.disconnect()
+    return flag_value
+
   def get_ticket_name(self, ticket_id):
     """Lookup ticket and return name as str."""
     name = None
@@ -451,6 +483,14 @@ class osTicket():
 
   def set_disk_passed(self, ticket_id):
     """Mark disk as passed in osTicket."""
+    current_value = self.get_flag(ticket_id, OSTICKET['Disk Flag']['Name'])
+
+    # Bail early?
+    if current_value == OSTICKET['Disk Flag']['Fail']:
+      print_warning('Not replacing osTicket disk checkbox FAILED value')
+      return
+
+    # Current value != FAILED, set to passed
     self.set_flag(
       ticket_id,
       OSTICKET['Disk Flag']['Name'],
@@ -458,7 +498,7 @@ class osTicket():
 
   def set_flag(self, ticket_id, flag_name, flag_value):
     """Set flag in osTicket."""
-    self.connect()
+    self.connect(silent=True)
 
     # Bail if disabled
     if self.disabled: