Different results on Test and in rails console when trying to create a unit test (Ruby on Rails)

I've been having problems with a test on a helper for a model on Ruby 2.0.0-p481, Rails 4.1.1, PostgreSQL 9.4 DB.

My helper is very simple. It finds on my Tract table the point(s) that are nearest (ties will exist) to the inputed lat, long pair:

module TractsHelper

  # returns rows (precalculated data) from the census tract point that is nearest given lat/log location
  def self.find_nearest(params)
    raise ArgumentError, 'Must supply starting latitude'  unless !params[:lat].nil?
    raise ArgumentError, 'Must supply starting longitude' unless !params[:lon].nil?

    nearest = Tract.select(:lat, :lon).order("(lat - #{params[:lat]})*(lat - #{params[:lat]}) + (lon - #{params[:lon]})*(lon - #{params[:lon]})").first

    if nearest.nil?
      tracts = Tract.none
    else
      tracts = Tract.where({:lat => nearest.lat, :lon => nearest.lon})
      #tracts = Tract.order("ST_Distance(POINT(#{params[:lat]}, #{params[:lon]}), POINT(lat, lon))")
    end
    return tracts
  end

end

Now, when I tried to write a test, this is what I came up with:

class TractsHelperTest < ActionView::TestCase
    def setup
          @input_lat = 47.7225472
          @input_lng = -122.2818937
    end

    test "return nearest census tract" do

        nearest_tract = TractsHelper.find_nearest({:lat => @input_lat, :lon => @input_lng})

        assert_equal @input_lat, nearest_tract.first.lat.to_f
        assert_equal @input_lng, nearest_tract.first.lon.to_f
    end
end

Since I know the values of @input_lat and @input_lng are a pair for a set of points in my table, this should return true for both assertions. However, I get:

Finished in 0.200984s, 4.9755 runs/s, 4.9755 assertions/s.

  1) Failure:
TractsHelperTest#test_return_nearest_tract [/home/ubuntu/workspace/myapp/test/helpers/tracts_helper_test.rb:13]:
Expected: 47.7225472
Actual: 0.0

1 runs, 1 assertions, 1 failures, 0 errors, 0 skips

Upon inspection, nearest_tract does return some results from the Tract model, but the value for nearest_tract.first.lat is nil, and so is every other value.

The funny thing is, when I try to replicate this test using the rails console, the results are good:

2.0.0-p481 :118 > @input_lat = 47.7225472
2.0.0-p481 :119 > @input_lng = -122.2818937
2.0.0-p481 :120 > nearest_tract = TractsHelper.find_nearest({:lat => @input_lat, :lon => @input_lng});
2.0.0-p481 :121 > @input_lat== nearest_tract.first.lat.to_f
 => true 
2.0.0-p481 :122 > @input_lng== nearest_tract.first.lon.to_f
 => true 

Which is really weird. Could anyone share some insights as to why the result is different depending on where I run the command / how to handle it?

Thanks!