Add testnet blockchain adapters again

lib/straight/gateway.rb

@@ -78,6 +78,10 @@ def blockchain_adapters
         @blockchain_adapters
       end
 
+      def test_blockchain_adapters
+        @blockchain_adapters.map{ |el| el.class.testnet_adapter rescue next }.compact
+      end
+
       # Creates a new order for the address derived from the pubkey and the keychain_id argument provided.
       # See explanation of this keychain_id argument is in the description for the AddressProvider::Base#new_address method.
       def new_order(args)

spec/lib/gateway_spec.rb

@@ -145,6 +145,7 @@
     it "is using testnet" do
       @gateway.test_mode = true
       allow(@mock_adapter).to receive(:testnet_adapters).and_return(true)
+      expect(@gateway.blockchain_adapters).to_not be nil
       expect(@gateway.blockchain_adapters).to eq(@gateway.test_blockchain_adapters)
     end