Properly (if convolutedly) query for empty strings

[sunspot#112 state:resolved]

sunspot/lib/sunspot/query/restriction.rb

@@ -149,10 +149,13 @@ def solr_value(value = @value)
       #
       class EqualTo < Base
         def to_positive_boolean_phrase
-          unless @value.nil?
-            super
-          else
+          case @value
+          when nil
             "#{escape(@field.indexed_name)}:[* TO *]"
+          when ''
+            %Q(#{escape(@field.indexed_name)}:[* TO ""])
+          else
+            super
           end
         end
 

sunspot/spec/api/query/scope_examples.rb

@@ -13,6 +13,13 @@
     connection.should have_last_search_including(:fq, 'title_ss:"OR"')
   end
 
+  it 'scopes by exact match with empty string' do
+    search do
+      with :title, ''
+    end
+    connection.should have_last_search_including(:fq, 'title_ss:[* TO ""]')
+  end
+
   it 'scopes by exact match with time' do
     time = Time.parse('1983-07-08 05:00:00 -0400')
     search do

sunspot/spec/integration/scoped_search_spec.rb

@@ -144,6 +144,31 @@ def self.test_field_type(name, attribute, field, *values)
     end
   end
 
+  describe 'empty strings' do
+    before :all do
+      Sunspot.remove_all
+      @posts = [Post.new(:title => ''), Post.new(:title => 'Bogus'), Post.new]
+      Sunspot.index!(@posts)
+    end
+
+    it 'should filter results with an empty string' do
+      search = Sunspot.search(Post) { with(:title, '') }
+      search.results.should == [@posts[0]]
+    end
+
+    it 'should not exclude results with non-empty string value' do
+      Sunspot.search(Post) { without(:title, '') }.results.should include(@posts[1])
+    end
+
+    it 'should not exclude results with no value' do
+      Sunspot.search(Post) { without(:title, '') }.results.should include(@posts[2])
+    end
+
+    it 'should exclude results with empty string value' do
+      Sunspot.search(Post) { without(:title, '') }.results.should_not include(@posts[0])
+    end
+  end
+
   describe 'prefix searching' do
     before :each do
       Sunspot.remove_all