adapt JSON parsing in tests to allow for omitted fields

features/support/route.rb

@@ -93,11 +93,13 @@ def route_status response
 end
 
 def extract_instruction_list instructions, index, postfix=nil
+  if instructions
     instructions.reject { |r| r[0].to_s=="#{DESTINATION_REACHED}" }.
     map { |r| r[index] }.
     map { |r| (r=="" || r==nil) ? '""' : "#{r}#{postfix}" }.
     join(',')
   end
+end
 
 def way_list instructions
   extract_instruction_list instructions, 1
@@ -112,6 +114,7 @@ def bearing_list instructions
 end
 
 def turn_list instructions
+  if instructions
     types = {
       0 => :none,
       1 => :straight,
@@ -140,6 +143,7 @@ def turn_list instructions
       end
     end.join(',')
   end
+end
 
 def mode_list instructions
   extract_instruction_list instructions, 8