diff --git a/lib/parser/keywords.citrus b/lib/parser/keywords.citrus
index 372ad0e..8fcc936 100644
--- a/lib/parser/keywords.citrus
+++ b/lib/parser/keywords.citrus
@@ -7,16 +7,22 @@ grammar Keywords
   rule keyword_do       'do'     space? end
   rule keyword_else     'else'   space?  end
   rule keyword_end      'end'    space?  end
-  rule keyword_false    'false'  space? end
   rule keyword_if       'if'     space?  end
   rule keyword_rescue   'rescue' space? end
   rule keyword_return   'return' space? end
   rule keyword_module   'module' space?  end
-  rule keyword_nil      'nil'    space? end
   rule keyword_unless   'unless' space? end
   rule keyword_until    'until'  space? end
   rule keyword_while    'while'  space? end
 
+  rule keyword_nil
+    ('nil'    space? ){ Ast::NilExpression.new }
+  end
+
+  rule keyword_false
+    ('false'  space?) { Ast::FalseExpression.new }
+  end
+
   rule keyword_true
     ('true'   space?) { Ast::TrueExpression.new }
   end
@@ -28,4 +34,9 @@ grammar Keywords
                    'unless' |  'until' |  'while') space?
   end
 
+  rule keyword_expression
+    keyword_true | keyword_false | keyword_nil
+  end
+
+  root  keyword_expression
 end
diff --git a/test/unit/test_basic.rb b/test/unit/test_basic.rb
index de23595..65523d6 100644
--- a/test/unit/test_basic.rb
+++ b/test/unit/test_basic.rb
@@ -1,23 +1,35 @@
-require_relative "../parser_helper"
+require_relative "../setup"
 
 class TestBasic < MiniTest::Test
   # include the magic (setup and parse -> test method translation), see there
-  include ParserHelper
+  #include ParserHelper
+
+  def setup
+    @parser = Keywords
+  end
+
+  def check
+    parse    = @parser.parse(@input)
+    assert_equal @input , parse
+    assert_equal @output , parse.value
+  end
 
   def test_true
     @input    = 'true '
     @output = Ast::TrueExpression.new()
-    @root = :keyword_true
+    check
   end
-  def ttest_false
+
+  def test_false
     @input    = 'false '
     @output = Ast::FalseExpression.new()
-    @root = :basic_type
+    check
   end
-  def ttest_nil
+
+  def test_nil
     @input    = 'nil '
     @output = Ast::NilExpression.new()
-    @root = :basic_type
+    check
   end
 
   def ttest_number