Seperate unit and integration tests.

This makes it easier to re-use the integration tests in a seperate gem that
optimizes parts of liquid with a native implementation.

test/integration/security_test.rb

@@ -0,0 +1,64 @@
+require 'test_helper'
+
+module SecurityFilter
+  def add_one(input)
+    "#{input} + 1"
+  end
+end
+
+class SecurityTest < Test::Unit::TestCase
+  include Liquid
+
+  def test_no_instance_eval
+    text = %( {{ '1+1' | instance_eval }} )
+    expected = %| 1+1 |
+
+    assert_equal expected, Template.parse(text).render!(@assigns)
+  end
+
+  def test_no_existing_instance_eval
+    text = %( {{ '1+1' | __instance_eval__ }} )
+    expected = %| 1+1 |
+
+    assert_equal expected, Template.parse(text).render!(@assigns)
+  end
+
+
+  def test_no_instance_eval_after_mixing_in_new_filter
+    text = %( {{ '1+1' | instance_eval }} )
+    expected = %| 1+1 |
+
+    assert_equal expected, Template.parse(text).render!(@assigns)
+  end
+
+
+  def test_no_instance_eval_later_in_chain
+    text = %( {{ '1+1' | add_one | instance_eval }} )
+    expected = %| 1+1 + 1 |
+
+    assert_equal expected, Template.parse(text).render!(@assigns, :filters => SecurityFilter)
+  end
+
+  def test_does_not_add_filters_to_symbol_table
+    current_symbols = Symbol.all_symbols
+
+    test = %( {{ "some_string" | a_bad_filter }} )
+
+    template = Template.parse(test)
+    assert_equal [], (Symbol.all_symbols - current_symbols)
+
+    template.render!
+    assert_equal [], (Symbol.all_symbols - current_symbols)
+  end
+
+  def test_does_not_add_drop_methods_to_symbol_table
+    current_symbols = Symbol.all_symbols
+
+    assigns = { 'drop' => Drop.new }
+    assert_equal "", Template.parse("{{ drop.custom_method_1 }}", assigns).render!
+    assert_equal "", Template.parse("{{ drop.custom_method_2 }}", assigns).render!
+    assert_equal "", Template.parse("{{ drop.custom_method_3 }}", assigns).render!
+
+    assert_equal [], (Symbol.all_symbols - current_symbols)
+  end
+end # SecurityTest