All tests in ImportedConfigurationClassEnhancementTests now pass. The fix was simple - imported @Configuration class bean definitions were not getting marked with the attribute that indicates that they are indeed @Configuration class bean definitions. To make this happen, ConfigurationClassPostProcessor's protected checkConfigurationClassCandidate(beanDef) method is being called from within ConfigurationClassBeanDefinitionReader when imported @Configuration classes are being processed. This is quick and dirty, and the subsequent check-in will refactor the solution appropriately.
