fix some word with tests

lib/soml/parfait/word.soml

@@ -1,9 +1,19 @@
 class Word < Object
-  int at(int index)
+
+  int char_at(int index)
+    index = index + 2
     return get_internal(index)
   end
-  Word add_digit( int i)
-    int l = self.char_length + 2
+
+  int set_length(int i)
+    set_internal( 2 , i)
+    return i
+  end
+
+  Word push_char(int i)
+    int l = self.char_length + 1
+    self.set_length(l)
+    l = l + 2
     set_internal( l , i)
     return self
   end

test/parfait/test_word.rb

@@ -0,0 +1,47 @@
+require_relative 'helper'
+
+class TestwordRT < MiniTest::Test
+  include RuntimeTests
+
+  def test_len
+    @string_input = <<HERE
+Word w = " "
+return w.char_length
+HERE
+    check_return 1
+  end
+
+  def test_space
+    @string_input = <<HERE
+Word w = " "
+return w.char_at(1)
+HERE
+    assert_equal 32 , " ".codepoints[0] # just checking
+    check_return 32
+  end
+
+  def test_add_doesnt_change1
+    @string_input = <<HERE
+Word w = " "
+w.push_char(32)
+return w.char_at(1)
+HERE
+    check_return 32
+  end
+  def test_after_add_get_works
+    @string_input = <<HERE
+Word w = " "
+w.push_char(32)
+return w.char_at(2)
+HERE
+    check_return 32
+  end
+  def test_after_add_length_works
+    @string_input = <<HERE
+Word w = " "
+w.push_char(32)
+return w.char_length
+HERE
+    check_return 2
+  end
+end