Part of lp.layers View In Hierarchy
PageTestLayer
layer. (need to register a 404 view for this and
for the debug page too. and make the debugview a base class in the
debug view and make system error, not found and unauthorized and
forbidden views.
This layer is applied to the request that is used for running page tests. Pages registered with this layer are accessible to pagetests but return 404s when visited interactively, so this should be used only for pages we want to maintain but not expose to users.
The SystemErrorView base class looks at the request to see if it provides this interface. If so, it renders tracebacks as plain text.