--- a/spec/util_interpolation_spec.lua	Sat Nov 16 16:52:31 2019 +0100
+++ b/spec/util_interpolation_spec.lua	Sun Nov 17 15:06:22 2019 +0100
@@ -17,6 +17,15 @@
 1. HELLO
 2. WORLD
 ]]
+local template_func_pipe = [[
+{foo|sort#{idx}. {item}
+}]]
+local expect_func_pipe = [[
+1. A
+2. B
+3. C
+4. D
+]]
 local template_map = [[
 {foo%{idx}: {item!}
 }]]
@@ -26,11 +35,12 @@
 
 describe("util.interpolation", function ()
 	it("renders", function ()
-		local render = require "util.interpolation".new("%b{}", string.upper);
+		local render = require "util.interpolation".new("%b{}", string.upper, { sort = function (t) table.sort(t) return t end });
 		assert.equal(expect1, render(template, { greet = "Hello", name = "world" }));
 		assert.equal(expect2, render(template, { greet = "Hello" }));
 		assert.equal(expect3, render(template, { name = "you" }));
 		assert.equal(expect_array, render(template_array, { foo = { "Hello", "World" } }));
+		assert.equal(expect_func_pipe, render(template_func_pipe, { foo = { "c", "a", "d", "b", } }));
 		assert.equal(expect_map, render(template_map, { foo = { foo = "bar" } }));
 	end);
 end);