Add testing specs for lib/set-plus
Add testing specs for lib/set-plus

Signed-off-by: Zhang Wei <d6fa6f3f4186ada68220f9e69e7ddc7f2c936bdf@lambdacloud.com>

phexus/lambda-util.js,sunyonggang/lambda-util.js,phexus/lambda-util.js,wezhang/lambda-util.js,sunyonggang/lambda-util.js,sky4star/lambda-util.js,lambdacloud/lambda-util.js,lambdacloud/lambda-util.js