irctest.server_tests.topic

“Once a user has joined a channel, he receives information about

all commands his server receives affecting the channel. This includes […] TOPIC” -- <https://tools.ietf.org/html/rfc1459#section-4.2.1> and <https://tools.ietf.org/html/rfc2812#section-3.2.1>

"If the topic of a channel is changed or cleared, every client in that

channel (including the author of the topic change) will receive a TOPIC command with the new topic as argument (or an empty argument if the topic was cleared) alerting them to how the topic has changed.

Clients joining the channel in the future will receive a RPL_TOPIC numeric (or lack thereof) accordingly." -- https://modern.ircdocs.horse/#topic-message

RFC2812 specifies ERR_NOTONCHANNEL as the correct response to TOPIC

on a nonexistent channel. The modern spec prefers ERR_NOSUCHCHANNEL.

<https://tools.ietf.org/html/rfc2812#section-3.2.4> <http://modern.ircdocs.horse/#topic-message>

“Once a user has joined a channel, he receives information about

all commands his server receives affecting the channel. This includes […] TOPIC” -- <https://tools.ietf.org/html/rfc1459#section-4.2.1> and <https://tools.ietf.org/html/rfc2812#section-3.2.1>

Test various cases related to RPL_NOTOPIC with set and unset topics.