support calling each_hash without block. returns enumerator

Author: kch

lib/sqlite3/resultset.rb

@@ -54,6 +54,7 @@ def each
     # Provides an internal iterator over the rows of the result set where
     # each row is yielded as a hash.
     def each_hash
+      return enum_for(__method__) unless block_given?
       while (node = next_hash)
         yield node
       end

test/test_result_set.rb

@@ -24,6 +24,12 @@ def test_each_hash
         assert_equal list[hash["a"] - 1], hash["b"]
       end
       rs.close
+
+      rs = @db.prepare("select * from foo").execute
+      rs.each_hash.to_a do |hash|
+        assert_equal list[hash["a"] - 1], hash["b"]
+      end
+      rs.close
     end
 
     def test_next_hash