Fix bug with deactivating Systems. Add test.

spec/tiny_spec.lua

@@ -138,6 +138,20 @@ describe('tiny-ecs:', function()
             assert.equals(timePassed, 0)
             assert.equals(entity1.xform.x, entityTemplate1.xform.x)
         end)
+
+        it("Disable and Enable Systems", function()
+            world:setSystemActive(moveSystem, false)
+            world:setSystemActive(oneTimeSystem, false)
+            world:update(1)
+            assert.equals(timePassed, 0)
+            assert.equals(entity1.xform.x, entityTemplate1.xform.x)
+            world:setSystemActive(moveSystem, true)
+            world:setSystemActive(oneTimeSystem, true)
+            world:update(1)
+            assert.equals(timePassed, 1)
+            assert.are_not.equal(entity1.xform.x, entityTemplate1.xform.x)
+        end)
+        
     end)
 
 end)

tiny.lua

@@ -389,7 +389,7 @@ end
 -- @param system A System in the World activate/deactivate
 -- @param active Boolean new state of the System
 function tiny.setSystemActive(world, system, active)
-    world.activeSystem[system] = active and true or nil
+    world.activeSystems[system] = active and true or nil
 end
 
 return tiny