Add a test for drawable:set_bgimage()

Signed-off-by: Uli Schlachter <psychon@znc.in>

tests/test-drawable-bgimage.lua

@@ -0,0 +1,56 @@
+local runner = require("_runner")
+local wibox = require("wibox")
+local beautiful = require("beautiful")
+local cairo = require("lgi").cairo
+
+local w = wibox {
+    x = 10,
+    y = 10,
+    width = 20,
+    height = 20,
+    visible = true,
+    bg = "#ff0000",
+}
+
+local callback_called
+local function callback(context, cr, width, height, arg)
+    assert(type(context) == "table", type(context))
+    assert(type(context.dpi) == "number", context.dpi)
+    assert(cairo.Context:is_type_of(cr), cr)
+    assert(width == 20, width)
+    assert(height == 20, height)
+    assert(arg == "argument: 42", arg)
+
+    callback_called = true
+end
+
+runner.run_steps({
+    -- Set some bg image
+    function()
+        local img = assert(beautiful.titlebar_close_button_normal)
+        w:set_bgimage(img)
+        return true
+    end,
+
+    -- Do nothing for a while iteration to give the repaint some time to happen
+    function(arg)
+        if arg == 3 then
+            return true
+        end
+    end,
+
+    -- Set some bg image function
+    function()
+        w:set_bgimage(callback, "argument: 42")
+        return true
+    end,
+
+    -- Wait for the function to be done
+    function()
+        if callback_called then
+            return true
+        end
+    end,
+})
+
+-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80