Expect an incompatible encoding exception when a template doesn't have a magic comment and its source encoding doesn't match the default external encoding

actionpack/test/fixtures/test/utf8.html.erb

@@ -1,4 +1,4 @@
-Русский текст
+Русский <%= "текст" %>
 <%= "日".encoding %>
 <%= @output_buffer.encoding %>
 <%= __ENCODING__ %>

actionpack/test/fixtures/test/utf8_magic.html.erb

@@ -1,5 +1,5 @@
 <%# encoding: utf-8 -%>
-Русский текст
+Русский <%= "текст" %>
 <%= "日".encoding %>
 <%= @output_buffer.encoding %>
 <%= __ENCODING__ %>

actionpack/test/template/render_test.rb

@@ -245,31 +245,6 @@ module RenderTestCases
     assert_equal %(\n<title>title</title>\n\n),
       @view.render(:file => "test/layout_render_file.erb")
   end
- 
-  if '1.9'.respond_to?(:force_encoding)
-    def test_render_utf8_template_with_magic_comment
-      with_external_encoding Encoding::ASCII_8BIT do
-        result = @view.render(:file => "test/utf8_magic.html.erb", :layouts => "layouts/yield")
-        assert_equal "Русский текст\nUTF-8\nUTF-8\nUTF-8\n", result
-        assert_equal Encoding::UTF_8, result.encoding
-      end
-    end
-
-    def test_render_utf8_template_with_default_external_encoding
-      with_external_encoding Encoding::UTF_8 do
-        result = @view.render(:file => "test/utf8.html.erb", :layouts => "layouts/yield")
-        assert_equal "Русский текст\nUTF-8\nUTF-8\nUTF-8\n", result
-        assert_equal Encoding::UTF_8, result.encoding
-      end
-    end
-
-    def with_external_encoding(encoding)
-      old, Encoding.default_external = Encoding.default_external, encoding
-      yield
-    ensure
-      Encoding.default_external = old
-    end
-  end
 end
 
 class CachedViewRenderTest < ActiveSupport::TestCase
@@ -302,4 +277,40 @@ class LazyViewRenderTest < ActiveSupport::TestCase
   def teardown
     GC.start
   end
+
+  if '1.9'.respond_to?(:force_encoding)
+    def test_render_utf8_template_with_magic_comment
+      with_external_encoding Encoding::ASCII_8BIT do
+        result = @view.render(:file => "test/utf8_magic.html.erb", :layouts => "layouts/yield")
+        assert_equal Encoding::UTF_8, result.encoding
+        assert_equal "Русский текст\nUTF-8\nUTF-8\nUTF-8\n", result
+      end
+    end
+
+    def test_render_utf8_template_with_default_external_encoding
+      with_external_encoding Encoding::UTF_8 do
+        result = @view.render(:file => "test/utf8.html.erb", :layouts => "layouts/yield")
+        assert_equal Encoding::UTF_8, result.encoding
+        assert_equal "Русский текст\nUTF-8\nUTF-8\nUTF-8\n", result
+      end
+    end
+
+    def test_render_utf8_template_with_incompatible_external_encoding
+      with_external_encoding Encoding::SJIS do
+        begin
+          result = @view.render(:file => "test/utf8.html.erb", :layouts => "layouts/yield")
+          flunk 'Should have raised incompatible encoding error'
+        rescue ActionView::Template::Error => error
+          assert_match 'invalid byte sequence in Shift_JIS', error.original_exception.message
+        end
+      end
+    end
+
+    def with_external_encoding(encoding)
+      old, Encoding.default_external = Encoding.default_external, encoding
+      yield
+    ensure
+      Encoding.default_external = old
+    end
+  end
 end