--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/muc_util_spec.lua	Sun Aug 19 13:20:55 2018 +0100
@@ -0,0 +1,35 @@
+local muc_util;
+
+local st = require "util.stanza";
+
+do
+	local old_pp = package.path;
+	package.path = "./?.lib.lua;"..package.path;
+	muc_util = require "plugins.muc.util";
+	package.path = old_pp;
+end
+
+describe("muc/util", function ()
+	describe("filter_muc_x()", function ()
+		it("correctly filters muc#user", function ()
+			local stanza = st.message({ to = "to", from = "from", id = "foo" })
+				:tag("x", { xmlns = "http://jabber.org/protocol/muc#user" })
+					:tag("invite", { to = "user@example.com" });
+
+			assert.equal(1, #stanza.tags);
+			assert.equal(stanza, muc_util.filter_muc_x(stanza));
+			assert.equal(0, #stanza.tags);
+		end);
+
+		it("correctly filters muc#user on a cloned stanza", function ()
+			local stanza = st.message({ to = "to", from = "from", id = "foo" })
+				:tag("x", { xmlns = "http://jabber.org/protocol/muc#user" })
+					:tag("invite", { to = "user@example.com" });
+
+			assert.equal(1, #stanza.tags);
+			local filtered = muc_util.filter_muc_x(st.clone(stanza));
+			assert.equal(1, #stanza.tags);
+			assert.equal(0, #filtered.tags);
+		end);
+	end);
+end);