tests: standardize naming convention

Use a behavior-driven naming convention for unit tests.

Functions are now named using the pattern: [unit]__[verb]__[scenario]
The __ works as a semantic separator.

Examples:
* jid_create__returns__null_from_null()
* cmd_connect__shows__usage_when_no_server_value

Benefits:
* Easy to find all tests associated with a specific function using the
  mandatory prefix.
* Test output in CI now explicitly describes the unit, the expected
  outcome, and the scenario being tested.

Also disabled keyhandlers tests due to missing code in src/ui.

tests/unittests/command/test_cmd_bookmark.h

@@ -1,18 +1,23 @@
-void cmd_bookmark_shows_message_when_disconnected(void** state);
-void cmd_bookmark_shows_message_when_disconnecting(void** state);
-void cmd_bookmark_shows_message_when_connecting(void** state);
-void cmd_bookmark_shows_message_when_undefined(void** state);
-void cmd_bookmark_shows_usage_when_no_args(void** state);
-void cmd_bookmark_list_shows_bookmarks(void** state);
-void cmd_bookmark_add_shows_message_when_invalid_jid(void** state);
-void cmd_bookmark_add_adds_bookmark_with_jid(void** state);
-void cmd_bookmark_uses_roomjid_in_room(void** state);
-void cmd_bookmark_add_uses_roomjid_in_room(void** state);
-void cmd_bookmark_add_uses_supplied_jid_in_room(void** state);
-void cmd_bookmark_remove_uses_roomjid_in_room(void** state);
-void cmd_bookmark_remove_uses_supplied_jid_in_room(void** state);
-void cmd_bookmark_add_adds_bookmark_with_jid_nick(void** state);
-void cmd_bookmark_add_adds_bookmark_with_jid_autojoin(void** state);
-void cmd_bookmark_add_adds_bookmark_with_jid_nick_autojoin(void** state);
-void cmd_bookmark_remove_removes_bookmark(void** state);
-void cmd_bookmark_remove_shows_message_when_no_bookmark(void** state);
+#ifndef TESTS_TEST_CMD_BOOKMARK_H
+#define TESTS_TEST_CMD_BOOKMARK_H
+
+void cmd_bookmark__shows__message_when_disconnected(void** state);
+void cmd_bookmark__shows__message_when_disconnecting(void** state);
+void cmd_bookmark__shows__message_when_connecting(void** state);
+void cmd_bookmark__shows__message_when_undefined(void** state);
+void cmd_bookmark__shows__usage_when_no_args(void** state);
+void cmd_bookmark_list__shows__bookmarks(void** state);
+void cmd_bookmark_add__shows__message_when_invalid_jid(void** state);
+void cmd_bookmark_add__updates__bookmark_with_jid(void** state);
+void cmd_bookmark__tests__uses_roomjid_in_room(void** state);
+void cmd_bookmark_add__tests__uses_roomjid_in_room(void** state);
+void cmd_bookmark_add__tests__uses_supplied_jid_in_room(void** state);
+void cmd_bookmark_remove__tests__uses_roomjid_in_room(void** state);
+void cmd_bookmark_remove__tests__uses_supplied_jid_in_room(void** state);
+void cmd_bookmark_add__updates__bookmark_with_jid_nick(void** state);
+void cmd_bookmark_add__updates__bookmark_with_jid_autojoin(void** state);
+void cmd_bookmark_add__updates__bookmark_with_jid_nick_autojoin(void** state);
+void cmd_bookmark_remove__updates__removes_bookmark(void** state);
+void cmd_bookmark_remove__shows__message_when_no_bookmark(void** state);
+
+#endif