tests: Add some memory-leak tests

This creates some random collection of widgets and tests if they can be garbage
collected again.

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

tests/test-leaks.lua

@@ -0,0 +1,49 @@
+-- Some memory leak checks as integration tests.
+
+local awful = require("awful")
+local cairo = require("lgi").cairo
+local create_wibox = require("_wibox_helper").create_wibox
+local gears = require("gears")
+local wibox = require("wibox")
+
+local errors = {}
+
+local prepare_for_collect = nil
+
+-- Test if some objects can be garbage collected
+local function collectable(a, b, c, d, e, f, g, h)
+    local objs = setmetatable({ a, b, c, d, e, f, g, h }, { __mode = "v" })
+    a, b, c, d, e, f, g, h = nil, nil, nil, nil, nil, nil, nil, nil
+    if prepare_for_collect then
+        prepare_for_collect()
+        prepare_for_collect = nil
+    end
+    collectgarbage("collect")
+    -- Check if the table is now empty
+    for k, v in pairs(objs) do
+        print("Some object was not garbage collected!")
+        error(v)
+    end
+end
+
+-- First test some basic widgets
+collectable(wibox.widget.base.make_widget())
+collectable(wibox.widget.textbox("foo"))
+collectable(wibox.layout.fixed.horizontal())
+collectable(wibox.layout.align.horizontal())
+
+-- Then some random widgets from awful
+collectable(awful.widget.launcher({ image = cairo.ImageSurface(cairo.Format.ARGB32, 20, 20), command = "bash" }))
+collectable(awful.widget.prompt())
+collectable(awful.widget.textclock())
+collectable(awful.widget.layoutbox(1))
+collectable(awful.widget.taglist(1, awful.widget.taglist.filter.all))
+
+-- And finally a full wibox
+function prepare_for_collect()
+    -- Only after doing the pending repaint can a wibox be GC'd.
+    awesome.emit_signal("refresh")
+end
+collectable(create_wibox())
+
+require("_runner").run_steps({ function() return true end })