BUY AND SELL TESTS

There are BUY TEST and SELL TEST which was proposed by Wyckoff in his Third law; Efforts versus results which signals a change in trend direction. But on the chart is only BUY TEST. Divergence between Volume and Price is used to detect this change.Is simple but powerful strategy...
FOR BUY TEST,
Buy when volume diminishes during reaction(like the chart above) and increase on rallies.
FOR SELL TEST,
Sell when volume decreases on rallies and increases on reaction.