Add test_class_tokenize_backtick_with_escape

Author: aycabta

test/test_rdoc_ruby_lex.rb

@@ -350,6 +350,51 @@ def test_class_tokenize_string
     assert_equal expected, tokens
   end
 
+  def test_class_tokenize_backtick_with_escape
+    tokens = RDoc::RubyLex.tokenize <<'RUBY', nil
+[
+  `\\`,
+  `\'\"\``,
+  `\#`,
+  `\#{}`,
+  `#`,
+  `#{}`
+]
+RUBY
+
+    expected = [
+      @TK::TkLBRACK  .new( 0, 1,  0, "["),
+      @TK::TkNL      .new( 1, 1,  1, "\n"),
+      @TK::TkSPACE   .new( 2, 2,  0, "  "),
+      @TK::TkXSTRING .new( 4, 2,  2, "`\\\\`"),
+      @TK::TkCOMMA   .new( 8, 2,  6, ","),
+      @TK::TkNL      .new( 9, 2,  2, "\n"),
+      @TK::TkSPACE   .new(10, 3,  0, "  "),
+      @TK::TkXSTRING .new(12, 3,  2, "`\\'\\\"\\``"),
+      @TK::TkCOMMA   .new(20, 3, 10, ","),
+      @TK::TkNL      .new(21, 3, 10, "\n"),
+      @TK::TkSPACE   .new(22, 4,  0, "  "),
+      @TK::TkXSTRING .new(24, 4,  2, "`\\#`"),
+      @TK::TkCOMMA   .new(28, 4,  6, ","),
+      @TK::TkNL      .new(29, 4, 22, "\n"),
+      @TK::TkSPACE   .new(30, 5,  0, "  "),
+      @TK::TkXSTRING .new(32, 5,  2, "`\\\#{}`"),
+      @TK::TkCOMMA   .new(38, 5,  8, ","),
+      @TK::TkNL      .new(39, 5, 30, "\n"),
+      @TK::TkSPACE   .new(40, 6,  0, "  "),
+      @TK::TkXSTRING .new(42, 6,  2, "`#`"),
+      @TK::TkCOMMA   .new(45, 6,  5, ","),
+      @TK::TkNL      .new(46, 6, 40, "\n"),
+      @TK::TkSPACE   .new(47, 7,  0, "  "),
+      @TK::TkDXSTRING.new(49, 7,  2, "`\#{}`"),
+      @TK::TkNL      .new(54, 7,  7, "\n"),
+      @TK::TkRBRACK  .new(55, 8,  0, "]"),
+      @TK::TkNL      .new(56, 8, 55, "\n")
+    ]
+
+    assert_equal expected, tokens
+  end
+
   def test_class_tokenize_string_escape
     tokens = RDoc::RubyLex.tokenize '"\\n"', nil
     assert_equal @TK::TkSTRING.new( 0, 1,  0, "\"\\n\""), tokens.first