align layout: Test signal emission

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

lib/wibox/layout/align.lua

@@ -139,18 +139,27 @@ end
 
 --- Set the layout's first widget. This is the widget that is at the left/top
 function align:set_first(widget)
+    if self.first == widget then
+        return
+    end
     self.first = widget
     self:emit_signal("widget::layout_changed")
 end
 
 --- Set the layout's second widget. This is the centered one.
 function align:set_second(widget)
+    if self.second == widget then
+        return
+    end
     self.second = widget
     self:emit_signal("widget::layout_changed")
 end
 
 --- Set the layout's third widget. This is the widget that is at the right/bottom
 function align:set_third(widget)
+    if self.third == widget then
+        return
+    end
     self.third = widget
     self:emit_signal("widget::layout_changed")
 end

spec/wibox/layout/align_spec.lua

@@ -222,6 +222,50 @@ describe("wibox.layout.align", function()
             end)
         end)
     end)
+
+    describe("emitting signals", function()
+        local layout, layout_changed
+        before_each(function()
+            layout = align.vertical()
+            layout:connect_signal("widget::layout_changed", function()
+                layout_changed = layout_changed + 1
+            end)
+            layout_changed = 0
+        end)
+
+        it("set first", function()
+            local w1, w2 = {}, {}
+            assert.is.equal(layout_changed, 0)
+            layout:set_first(w1)
+            assert.is.equal(layout_changed, 1)
+            layout:set_first(w2)
+            assert.is.equal(layout_changed, 2)
+            layout:set_first(w2)
+            assert.is.equal(layout_changed, 2)
+        end)
+
+        it("set second", function()
+            local w1, w2 = {}, {}
+            assert.is.equal(layout_changed, 0)
+            layout:set_second(w1)
+            assert.is.equal(layout_changed, 1)
+            layout:set_second(w2)
+            assert.is.equal(layout_changed, 2)
+            layout:set_second(w2)
+            assert.is.equal(layout_changed, 2)
+        end)
+
+        it("set third", function()
+            local w1, w2 = {}, {}
+            assert.is.equal(layout_changed, 0)
+            layout:set_third(w1)
+            assert.is.equal(layout_changed, 1)
+            layout:set_third(w2)
+            assert.is.equal(layout_changed, 2)
+            layout:set_third(w2)
+            assert.is.equal(layout_changed, 2)
+        end)
+    end)
 end)
 
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