refactor: Split topic_command_cb and add tests

Split out the parts of topic_command_cb that's most interesting and
easiest to test into parse_topic_command and add tests for that
function.

2 files changed, 69 insertions, 16 deletions

diff --git a/_pytest/test_topic_command.py b/_pytest/test_topic_command.py
new file mode 100644
index 0000000..2a4f069
--- /dev/null
+++ b/_pytest/test_topic_command.py
@@ -0,0 +1,44 @@
+from wee_slack import parse_topic_command
+
+
+def test_parse_topic_without_arguments():
+    channel_name, topic = parse_topic_command('/topic')
+
+    assert channel_name is None
+    assert topic is None
+
+
+def test_parse_topic_with_text():
+    channel_name, topic = parse_topic_command('/topic some topic text')
+
+    assert channel_name is None
+    assert topic == 'some topic text'
+
+
+def test_parse_topic_with_delete():
+    channel_name, topic = parse_topic_command('/topic -delete')
+
+    assert channel_name is None
+    assert topic == ''
+
+
+def test_parse_topic_with_channel():
+    channel_name, topic = parse_topic_command('/topic #general')
+
+    assert channel_name == 'general'
+    assert topic is None
+
+
+def test_parse_topic_with_channel_and_text():
+    channel_name, topic = parse_topic_command(
+        '/topic #general some topic text')
+
+    assert channel_name == 'general'
+    assert topic == 'some topic text'
+
+
+def test_parse_topic_with_channel_and_delete():
+    channel_name, topic = parse_topic_command('/topic #general -delete')
+
+    assert channel_name == 'general'
+    assert topic == ''
diff --git a/wee_slack.py b/wee_slack.py
index 37db0ec..46ad278 100644
--- a/wee_slack.py
+++ b/wee_slack.py
@@ -2825,6 +2825,28 @@ def part_command_cb(data, current_buffer, args):
     return w.WEECHAT_RC_OK_EAT
 
 
+def parse_topic_command(command):
+    args = command.split()[1:]
+    channel_name = None
+    topic = None
+
+    if args:
+        if args[0].startswith('#'):
+            channel_name = args[0][1:]
+            topic = args[1:]
+        else:
+            topic = args
+
+    if topic == []:
+        topic = None
+    if topic:
+        topic = ' '.join(topic)
+    if topic == '-delete':
+        topic = ''
+
+    return channel_name, topic
+
+
 @slack_buffer_or_ignore
 def topic_command_cb(data, current_buffer, command):
     """
@@ -2833,18 +2855,10 @@ def topic_command_cb(data, current_buffer, command):
     """
     data = decode_from_utf8(data)
     command = decode_from_utf8(command)
-    team = EVENTROUTER.weechat_controller.buffers[current_buffer].team
 
-    args = command.split()[1:]
-    channel_name = None
-    topic = []
-    if args:
-        if args[0].startswith('#'):
-            channel_name = args[0][1:]
-            topic = args[1:]
-        else:
-            topic = args
+    channel_name, topic = parse_topic_command(command)
 
+    team = EVENTROUTER.weechat_controller.buffers[current_buffer].team
     if channel_name:
         channel = team.channels.get(team.get_channel_map().get(channel_name))
     else:
@@ -2854,12 +2868,7 @@ def topic_command_cb(data, current_buffer, command):
         w.prnt(team.channel_buffer, "#{}: No such channel".format(channel_name))
         return w.WEECHAT_RC_OK_EAT
 
-    if topic:
-        topic = ' '.join(topic)
-    if topic == '-delete':
-        topic = ''
-
-    if topic == []:
+    if topic is None:
         w.prnt(channel.channel_buffer, 'Topic for {} is "{}"'.format(channel.name, channel.slack_topic['value']))
     else:
         s = SlackRequest(team.token, "channels.setTopic", {"channel": channel.identifier, "topic": topic}, team_hash=team.team_hash)