Fixed call to Disc#toc_string with native implementation

Author: phw

lib/discid/disc.rb

@@ -145,7 +145,7 @@ def mcn
     # @return [String] The TOC string or `nil` if no ID was yet read.
     def toc_string
       return nil if not @read
-      result = Lib.get_toc_string
+      result = Lib.get_toc_string @handle
       if not result
         # probably an old version of libdiscid (< 0.6.0)
         # gather toc string from submission_url

test/test_disc.rb

@@ -85,4 +85,10 @@ def test_put
     assert_equal @fiction_lengths, disc.tracks.map{|t| t.sectors}
   end
 
+  def test_toc_string
+    disc = DiscId.put(@fiction_first_track, @fiction_sectors, @fiction_offsets)
+    expected_toc = '1 10 206535 150 18901 39738 59557 79152 100126 124833 147278 166336 182560'
+    assert_equal expected_toc, disc.toc_string
+  end
+
 end