If during a reversal, price action comes back on contracting volume, the reversal has been tested.

Biotech, IBB has done just that. It’s a near textbook example.
Today was upward action. An exact Fibonacci 61.8%, retrace of the three-day move with volume contracting over 41% from the prior session.
Under such conditions, there’s high probability of an immediate resumption of the reversal trend.
We’ll see if biotech (IBB) resumes the downward reversal at the next session; Tomorrow, Friday.
Market positions remain unchanged (not advice, not a recommendation) and shown below
Managed Accounts
Detail Position Stop
Short GDX DUST 20.44
Short IBB BIS 25.46
Charts by StockCharts