River Test providing business (10)
I believe the answer is:
industrial
'business' is the definition.
(thesaurus)
'river test' is the wordplay.
'river' becomes 'indus' (Indus River is an example**).
'test' becomes 'trial' ('trial' can be a synonym of 'test').
'indus'+'trial'='INDUSTRIAL'
'providing' is the link.
(Other definitions for industrial that I've seen before include "Type of action" , "Relating to manufacture" , "Inlaid rust (anag.)" , "Characterised by manufacturing processes" , "plants may be so described" .)