Exception handling for humans

Ability to pass exception_handler as a block to #render
and provide whatever behavior you want on handling exceptions

https://github.com/Shopify/liquid/pull/254

test/integration/template_test.rb

@@ -153,4 +153,18 @@ class TemplateTest < Test::Unit::TestCase
     end
     assert_equal 'ruby error in drop', e.message
   end
+
+  def test_exception_handler_doesnt_reraise_if_it_returns_false
+    exception = nil
+    Template.parse("{{ 1 | divided_by: 0 }}").render({}, exception_handler: ->(e) { exception = e; false })
+    assert exception.is_a?(ZeroDivisionError)
+  end
+
+  def test_exception_handler_does_reraise_if_it_returns_true
+    exception = nil
+    assert_raises(ZeroDivisionError) do
+      Template.parse("{{ 1 | divided_by: 0 }}").render({}, exception_handler: ->(e) { exception = e; true })
+    end
+    assert exception.is_a?(ZeroDivisionError)
+  end
 end