💄 Fix ugly test

spec/display-buffer-spec.coffee

@@ -1051,8 +1051,8 @@ describe "DisplayBuffer", ->
       expect(displayBuffer.decorationsForScreenRowRange(2, 3)[marker.id][0]).toBe decoration
 
       decoration.destroy()
-      expect(!!displayBuffer.decorationsForScreenRowRange(2, 3)[marker.id]).toBeFalsy()
-      expect(!!displayBuffer.decorationForId(decoration.id)).toBeFalsy()
+      expect(displayBuffer.decorationsForScreenRowRange(2, 3)[marker.id]).not.toBeDefined()
+      expect(displayBuffer.decorationForId(decoration.id)).not.toBeDefined()
 
     it "will not fail if the decoration is removed twice", ->
       decoration.destroy()