I have no idea if this is related to #1001, but it seems less weird.
Renames erroneously named email template for AdminMailer.
Adds tests for UserMailer to ensure correct email templates are being rendered.
Fixes path to artifact in email templates for UserMailer and AdminMailer.
Adds tests for AdminMailer to ensure we're rendering an email with relevant info.
Changes link in admin email template to use catalog_path helper.
Adds PathHelpers to spec/spec_helper.rb, so that catalog_path and friends are available in tests.
Merge pull request #1011 from afred/might-fix-email-1001

@afred: looks good to me. At some point, I got the sense that there were existing tests that were bad, but maybe they just had gaps that are now filled? In any case, I'm merging.