Add sketch of I18n error translation

test/liquid/i18n_test.rb

@@ -0,0 +1,33 @@
+require 'test_helper'
+
+class I18nTest < Test::Unit::TestCase
+  include Liquid
+
+  def setup
+    @i18n = I18n.new("./test/fixtures/en_locale.yml")
+  end
+
+  def test_simple_translate_string
+    assert_equal "less is more", @i18n.translate("simple")
+  end
+
+  def test_nested_translate_string
+    assert_equal "something wasn't right", @i18n.translate("errors.syntax.oops")
+  end
+
+  def test_single_string_interpolation
+    assert_equal "something different", @i18n.translate("whatever", :something => "different")
+  end
+
+  def test_raises_keyerror_on_undefined_interpolation_key
+    assert_raise I18n::TranslationError do
+      @i18n.translate("whatever", :oopstypos => "yes")
+    end
+  end
+  
+  def test_raises_unknown_translation
+    assert_raise I18n::TranslationError do
+      @i18n.translate("doesnt_exist")
+    end
+  end
+end