Update test to cover multiple consecutive dashes in identifiers.

lib/liquid/lexer.rb

@@ -13,7 +13,7 @@ module Liquid
       '?'.freeze => :question,
       '-'.freeze => :dash
     }
-    IDENTIFIER = /[a-zA-Z_][\w-]*\??/
+    IDENTIFIER = /[a-zA-Z_](?:[\w-]*\w)?\??/
     SINGLE_STRING_LITERAL = /'[^\']*'/
     DOUBLE_STRING_LITERAL = /"[^\"]*"/
     NUMBER_LITERAL = /-?\d+(\.\d+)?/

test/unit/lexer_unit_test.rb

@@ -36,6 +36,9 @@ class LexerUnitTest < Minitest::Test
 
     tokens = Lexer.new('2foo').tokenize
     assert_equal [[:number, '2'], [:id, 'foo'], [:end_of_string]], tokens
+
+    tokens = Lexer.new('foo-bar--baz-').tokenize
+    assert_equal [[:id, 'foo-bar--baz'], [:dash, "-"], [:end_of_string]], tokens
   end
 
   def test_whitespace