fix bug when no previous message

spotbot.py

@@ -13,8 +13,11 @@ def __init__(self, http_req, table, discord_http):
     def process(self):
         logging.info('Processing HamAlert message')
         previous_message, message_id = self.get_last_message()
-        previous_message = self.strikethrough_mesage(previous_message)
-        content = self.combine_messages(previous_message, self.ham)
+        if previous_message:
+            previous_message = self.strikethrough_mesage(previous_message)
+            content = self.combine_messages(previous_message, self.ham)
+        else:
+            content = str(self.ham)
         message_id = self.discord_http.post_message(content, message_id)
         self.table.upsert_entity(self.ham.callsign, message_id)
 

test.py

@@ -13,6 +13,15 @@ def test_spotbot(self):
         dt = sb.ham.received_time_pt.strftime("%H:%M")
         self.assertEqual(sb.discord_http.posted_message, f"~~01:05 | KI7HSG | [pota](https://api.pota.app/spot/comments/KI7HSG/US-0052) | freq: 14.074 | mode: FT8 | loc: US-0052~~\n{dt} | KI7HSG | [sotawatch](https://sotl.as/activators/KI7HSG) | freq: 14.074 | mode: FT8 | loc: ABCD")
 
+    def test_spotbot_2(self):
+        sb = spotbot.SpotBot(FakeHttpRequest(), table=FakeHamAlertTable(None), discord_http=FakeDiscordHttp())
+        sb.process()
+        self.assertEqual(sb.table.saved_callsign, "KI7HSG")
+        self.assertEqual(sb.table.saved_messageId, "9876")
+        dt = sb.ham.received_time_pt.strftime("%H:%M")
+        self.assertEqual(sb.discord_http.posted_message, f"{dt} | KI7HSG | [sotawatch](https://sotl.as/activators/KI7HSG) | freq: 14.074 | mode: FT8 | loc: ABCD")
+
+
 '''
 Fake classes for testing
 '''