Relax tests

Author: YingboMa

test/Thermal/thermal.jl

@@ -240,7 +240,7 @@ end
     @test sol.retcode == Success
     @test sol[T_winding.T] == sol[winding.T]
     @test sol[T_core.T] == sol[core.T]
-    @test sol[-core.port.Q_flow] ==
+    @test sol[-core.port.Q_flow] ≈
           sol[coreLosses.port.Q_flow + convection.solid.Q_flow + winding2core.port_b.Q_flow]
     @test sol[T_winding.T][end] >= 500 # not good but better than nothing
     @test sol[T_core.T] <= sol[T_winding.T]