Add test for nautical miles distance calculation.

test/calculations_test.rb

@@ -38,6 +38,12 @@ class CalculationsTest < Test::Unit::TestCase
     assert (la_to_ny - 3942).abs < 10
   end
 
+  def test_distance_between_in_nautical_miles
+    assert_equal 60, Geocoder::Calculations.distance_between([0,0], [0,1], :units => :nm).round
+    la_to_ny = Geocoder::Calculations.distance_between([34.05,-118.25], [40.72,-74], :units => :nm).round
+    assert (la_to_ny - 2124).abs < 10
+  end
+
 
   # --- geographic center ---