Test brief page for legacy briefs and legacy flow
Test brief page for legacy briefs and legacy flow

These two extra classes test the opportunity page with the new flow
active but with a legacy brief. It also tests the page with the feature
flag set to false

alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend