diff --git a/spec/lrama/new_lexer_spec.rb b/spec/lrama/new_lexer_spec.rb
new file mode 100644
index 00000000..89ba3f0b
--- /dev/null
+++ b/spec/lrama/new_lexer_spec.rb
@@ -0,0 +1,279 @@
+RSpec.describe Lrama::NewLexer do
+  Token = Lrama::Lexer::Token
+
+  describe '#next_token' do
+    context 'basic.y' do
+      it do
+        text = File.read(fixture_path("common/basic.y"))
+        lexer = Lrama::NewLexer.new(text)
+
+        expect(lexer.next_token).to eq(['%require', '%require'])
+        expect(lexer.next_token).to eq([:STRING, '"3.0"'])
+        expect(lexer.next_token).to eq(['%{', '%{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '%}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n// Prologue\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['%}', '%}'])
+        expect(lexer.next_token).to eq(['%expect', '%expect'])
+        expect(lexer.next_token).to eq([:INTEGER, 0])
+        expect(lexer.next_token).to eq(['%define', '%define'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'api.pure')])
+        expect(lexer.next_token).to eq(['%define', '%define'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'parse.error')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'verbose')])
+        expect(lexer.next_token).to eq(['%printer', '%printer'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n    print_int();\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<int>')])
+        expect(lexer.next_token).to eq(['%printer', '%printer'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n    print_token();\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tNUMBER')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq(['%lex-param', '%lex-param'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: 'struct lex_params *p')])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['%parse-param', '%parse-param'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: 'struct parse_params *p')])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['%initial-action', '%initial-action'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n    initial_action_func(@$);\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq(['%union', '%union'])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n    int i;\n    long l;\n    char *str;\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'EOI')])
+        expect(lexer.next_token).to eq([:INTEGER, 0])
+        expect(lexer.next_token).to eq([:STRING, '"EOI"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'\\\\'")])
+        expect(lexer.next_token).to eq([:STRING, '"backslash"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'\\13'")])
+        expect(lexer.next_token).to eq([:STRING, '"escaped vertical tab"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_class')])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_class2')])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<l>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tNUMBER')])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<str>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_end')])
+        expect(lexer.next_token).to eq([:STRING, '"end"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tPLUS')])
+        expect(lexer.next_token).to eq([:STRING, '"+"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tMINUS')])
+        expect(lexer.next_token).to eq([:STRING, '"-"'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tEQ')])
+        expect(lexer.next_token).to eq([:STRING, '"="'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tEQEQ')])
+        expect(lexer.next_token).to eq([:STRING, '"=="'])
+        expect(lexer.next_token).to eq(['%type', '%type'])
+        expect(lexer.next_token).to eq([:TAG, Token.new(type: Token::Tag, s_value: '<i>')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'class')])
+        expect(lexer.next_token).to eq(['%nonassoc', '%nonassoc'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tEQEQ')])
+        expect(lexer.next_token).to eq(['%left', '%left'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tPLUS')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tMINUS')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'>'")])
+        expect(lexer.next_token).to eq(['%right', '%right'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tEQ')])
+        expect(lexer.next_token).to eq(['%%', '%%'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'program')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'class')])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'+'")])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'strings_1')])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'-'")])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'strings_2')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'class')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_class')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_end')])
+        expect(lexer.next_token).to eq(['%prec', '%prec'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tPLUS')])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: " code 1 ")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_class')])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: " code 2 ")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'!'")])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_end')])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: " code 3 ")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['%prec', '%prec'])
+        expect(lexer.next_token).to eq([:STRING, '"="'])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_class')])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: " code 4 ")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'?'")])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'keyword_end')])
+        expect(lexer.next_token).to eq(['{', '{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: " code 5 ")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['}', '}'])
+        expect(lexer.next_token).to eq(['%prec', '%prec'])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'>'")])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'strings_1')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'string_1')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'strings_2')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'string_1')])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'string_2')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'string_1')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'string')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'string_2')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'string')])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'+'")])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'string')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tSTRING')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq(['%%', '%%'])
+        expect(lexer.next_token).to eq(nil)
+      end
+    end
+
+    context 'nullable.y' do
+      it do
+        text = File.read(fixture_path("common/nullable.y"))
+        lexer = Lrama::NewLexer.new(text)
+
+        expect(lexer.next_token).to eq(['%require', '%require'])
+        expect(lexer.next_token).to eq([:STRING, '"3.0"'])
+        expect(lexer.next_token).to eq(['%{', '%{'])
+
+        lexer.status = :c_declaration; lexer.end_symbol = '%}'
+        expect(lexer.next_token).to eq([:C_DECLARATION, Token.new(type: Token::User_code, s_value: "\n// Prologue\n")])
+        lexer.status = :initial
+
+        expect(lexer.next_token).to eq(['%}', '%}'])
+        expect(lexer.next_token).to eq(['%token', '%token'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tNUMBER')])
+        expect(lexer.next_token).to eq(['%%', '%%'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'program')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'stmt')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'stmt')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'expr')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'opt_semicolon')])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'opt_expr')])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'opt_colon')])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'expr')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'tNUMBER')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'opt_expr')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:IDENTIFIER, Token.new(type: Token::Ident, s_value: 'expr')])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'opt_semicolon')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "';'")])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq([:IDENT_COLON, Token.new(type: Token::Ident, s_value: 'opt_colon')])
+        expect(lexer.next_token).to eq([':', ':'])
+        expect(lexer.next_token).to eq(['|', '|'])
+        expect(lexer.next_token).to eq([:CHARACTER, Token.new(type: Token::Char, s_value: "'.'")])
+        expect(lexer.next_token).to eq([';', ';'])
+        expect(lexer.next_token).to eq(['%%', '%%'])
+        expect(lexer.next_token).to eq(nil)
+      end
+    end
+  end
+end