diff --git a/spec/tiny_spec.lua b/spec/tiny_spec.lua
index 40660ae..23bba4b 100644
--- a/spec/tiny_spec.lua
+++ b/spec/tiny_spec.lua
@@ -179,6 +179,24 @@ describe('tiny-ecs:', function()
             assert.equals(0, world:getEntityCount())
         end)
 
+        it("Add Systems Multiple Times", function()
+            world:update(1)
+            world:add(moveSystem, oneTimeSystem)
+            world:update(2)
+            assert.equals(2, world:getSystemCount())
+            assert.equals(3, world:getEntityCount())
+        end)
+
+        it("Remove Systems Multiple Times", function()
+            world:update(1)
+            world:remove(moveSystem)
+            world:update(2)
+            world:remove(moveSystem)
+            world:update(2)
+            assert.equals(1, world:getSystemCount())
+            assert.equals(3, world:getEntityCount())
+        end)
+
     end)
 
 end)