brew.py: Handle empty search results from API

Fixes #559

.coveragerc

@@ -11,3 +11,4 @@ exclude_lines =
 [run]
 omit =
     tests/data/*
+    tests/util/*

plugins/brew.py

@@ -29,6 +29,9 @@ def brew(text, reply):
 
     try:
         if 'totalResults' in response:
+            if response['totalResults'] == 0:
+                return output
+
             beer = response['data'][0]
             brewery = beer['breweries'][0]
 

tests/plugin_tests/test_brew.py

@@ -0,0 +1,24 @@
+from mock import MagicMock
+
+from tests.util.mock_bot import MockBot
+
+
+def test_no_results(mock_requests, unset_bot):
+    from cloudbot.bot import bot
+
+    bot.set(MockBot({"api_keys": {"brewerydb": "APIKEY"}}))
+    mock_requests.add(
+        'GET',
+        'http://api.brewerydb.com/v2/search'
+        '?format=json&key=APIKEY&type=beer&withBreweries=Y&q=some+text',
+        match_querystring=True,
+        json={"totalResults": 0},
+    )
+    from plugins import brew
+
+    reply = MagicMock()
+    result = brew.brew('some text', reply)
+
+    reply.assert_not_called()
+
+    assert result == 'No results found.'

tests/util/mock_bot.py

@@ -0,0 +1,17 @@
+import asyncio
+
+from cloudbot.config import Config
+
+
+class MockConfig(Config):
+    def load_config(self):
+        self._api_keys.clear()
+
+
+class MockBot:
+    def __init__(self, config, loop=None):
+        if loop is None:
+            loop = asyncio.get_event_loop()
+
+        self.loop = loop
+        self.config = MockConfig(self, config)