One of the criteria for passing the Bona Fide Residence Test is:
A U.S. citizen who is a resident of a foreign country, or countries, for an uninterrupted period that includes an entire tax year (January 1–December 31).

So just to be completely clear on this, if I've been living in a country since 1984 and moved to the US in September 2011. When filing the 2555-EZ for 2011 would I pass the above test, even though I was not a resident in the foreign country throughout the whole year of 2011?

Thanks!

“One of the criteria for passing the Bona Fide Residence Test is:A U.S. citizen who is a resident of a foreign country, or countries, for an uninterrupted period that includes an entire tax year (January 1–December 31).”--->Correct; this means , for example, to qualify as a BFRT, you must be in a foreign country at least on Dec 31 of a certain calendar year, NOT on Jan 1 of a certain calendar year.
“So just to be completely clear on this, if I've been living in a country since 1984 and moved to the US in September 2011. When filing the 2555-EZ for 2011 would I pass the above test, even though I was not a resident in the foreign country throughout the whole year of 2011?”----> You must reaffirm your status each year for FEIE deduction(juat like PPT). Once you have established bona fide residence in a foreign country for an uninterrupted period that includes an entire tax year, you will qualify as a bona fide resident for the period starting with the date you actually began the residence and ending with the date you abandon the foreign residence. You could qualify as a bona fide resident for an entire tax year plus parts of 1 or 2 other tax year;for example, assume that you were a bona fide resident of UK from March 1, 2006, through September 14, 2008(as you returned to US after Sep 14 2008).Then, on September 15, 2008, you returned to the US. Since you were a bona fide resident of a foreign country for all of 2007(from March 1 2006-Feb 28 2007), as described above, you also qualify as a bona fide resident from March 1, 2006, through the end of 2006 and from January 1, 2008, through September 14, 2008 just before your returning to US. After Sep 14, 2008, you are NO longer a BFR of a foreign country.

Thanks!
So if I take your example above - if I were to fill out a form 2555-EZ form for the year 2008 - would the answer to question 1a. (Were you a bona fide resident of a foreign country or countries for a period that includes an entire tax year?) then be - NO?

So if I take your example above - if I were to fill out a form 2555-EZ form for the year 2008 - would the answer to question 1a. (Were you a bona fide resident of a foreign country or countries for a period that includes an entire tax year?) then be - NO?”--->You were a BFR(as IO assuem that yu passed BERT in a foreign country) from 1984-Sep 2011, then yes. You were a BFR in a foreign country in 2008(I mean from 2008-Sep 2011).So, you can be a BFR on your 2008 US return.