IRS Publication 969 speaks to any HSA questions. You can contribute for 2014 (April 15, 2015 contribution deadline) if you had an HSA SET UP by December 1, 2014.
Publication 969:
Last-month rule. Under the last-month rule, if you are an eligible individual on the first day of the last month of your tax year (December 1 for most taxpayers), you are considered an eligible individual for the entire year. You are treated as having the same HDHP coverage for the entire year as you had on the first day of the last month.
Testing period. If contributions were made to your HSA based on you being an eligible individual for the entire year under the last-month rule, you must remain an eligible individual during the testing period. For the last-month rule, the testing period begins with the last month of your tax year and ends on the last day of the 12th month following that month. For example, December 1, 2013, through December 31, 2014.