How do you test your landing pages? Is using the same ad and 2 different landing pages the only way to test landing pages?
You can use two ads with 2 landing pages for testing.. but then you will never understand if your ad affected the CTR or the LP.... When testing, always test only one of the variables keeping rest constant...
That is right only change one variables. what means that you have one ad pointing to two landing pages and you do this for a amount of time giving you enough data to decide which one works better
Don't do the above as it's not a fair test. Google doesn't split 2 adgroups 50/50. Do what's been advised above, Ad A + Ad B, both exactly the same to the user, but Ad A goes to one page and Ad B goes to a different one. Make sure you run the ads long enough. In my experience this is until at least one of the Ads has reached 30 clicks. If the results aren't obvious then run up to 40 clicks, 50 clicks etc. Drop the keyword bid around 10-15% if a) the ROI/cost per conversion is too high and b) the results are too close after 30 clicks. If the keyword is working (making you profit) then leave the bid as it is.
I second what Muchacho said. You need to have your ads in the same group. The same ad but going to the different landing pages you want to test.