diff --git a/source/bot.py b/source/bot.py
index 3224e41..3012c81 100644
--- a/source/bot.py
+++ b/source/bot.py
@@ -565,7 +565,7 @@ def add_product(message):
     user_id = message.from_user.id
 
     # Check if user is admin
-    if not session.query(User).filter(User.telegram_id==user_id).first().admin:
+    if not session.query(User).filter(User.telegram_id == user_id).first().admin:
         bot.reply_to(message, "Error: Admin rights are required to add products")
         return
 
@@ -619,6 +619,9 @@ def receive_product_data(message):
     except sqlalchemy.exc.IntegrityError:
         session.rollback()
         bot.send_message(chat_id=user_id, text='Product is in database already')
+    except pymysql.err.OperationalError:
+        session.rollback()
+        bot.send_message(chat_id=user_id, text='Unknown error')
 
 
 @bot.callback_query_handler(func=lambda call: True)
diff --git a/source/fetcher.py b/source/fetcher.py
index f411536..67e7223 100644
--- a/source/fetcher.py
+++ b/source/fetcher.py
@@ -20,6 +20,11 @@ def fetch_url(url):
 
     Raises:
         None: None
+
+    Test:
+        What happens if url returns non 200 status code
+        What happens if url returns 200 status code
+        What happens if Firefox, Gecko or important libraries are not installed
     """
     display = Display(visible=False, size=(800, 600))
     display.start()
@@ -57,6 +62,11 @@ def get_title(response):
 
     Raises:
         None: None
+
+    Test:
+        Response contains meta tag with title attribute
+        Response doesn't contain meta tag
+        Response is invalid html
     """
     soup = BeautifulSoup(response, 'html.parser')
 
@@ -79,6 +89,12 @@ def get_image(response):
 
     Raises:
         None: None
+
+    Test:
+        Response contains div with "imgTagWrapperId" id and includes json data
+        Response doesn't contain div
+        Response is invalid html
+        JSON is not valid
     """
     soup = BeautifulSoup(response, 'html.parser')
 
@@ -111,6 +127,11 @@ def get_description(response):
 
     Raises:
         None: None
+
+    Test:
+        Response contains div with "feature-bullets" id
+        Response doesn't contain div
+        Response is invalid html
     """
     soup = BeautifulSoup(response, 'html.parser')
 
@@ -139,6 +160,13 @@ def get_price(response):
 
     Raises:
         None: None
+
+    Test:
+        Response contains div with class "twister-plus-buying-options-price-data"
+        Response doesn't contain div
+        No valid JSON
+        Only price, currency missing
+        Response is invalid html
     """
     soup = BeautifulSoup(response, 'html.parser')