Saga basic concept and unit test reference list

In DDD/CQRS, A saga is a “long-lived business transaction or process between aggregates”, also call process manager

http://blog.jonathanoliver.com/cqrs-sagas-with-event-sourcing-part-i-of-ii/
http://blog.jonathanoliver.com/cqrs-sagas-with-event-sourcing-part-ii-of-ii/
How to unit test saga
http://www.udidahan.com/2008/02/04/sagas-and-unit-testing-business-process-verification-made-easy/
http://docs.particular.net/nservicebus/sagas/

How much code coverage do you really need?

http://software-development-thoughts.blogspot.ca/2011/04/how-much-code-coverage-do-you-really.html

Two quotes from Uncle Bob
“Two things. Repeatability and cost. Manual tests are horrifically expensive compared to automated tests.”

“Manual tests aren't tests; they are trials. And since there are humans involved, they are suspect."

Tree of programming languages

http://commons.wikimedia.org/wiki/File:Genealogical_tree_of_programming_languages.svg

Last line effect

We expose the “last line effect,” the phenomenon that the last line or statement in a micro-clone is much more likely to contain an error than the previous lines or statements. We do this by analyzing 208 open source projects and reporting on 202 faulty micro-clones.


x += o t h e r . x ;
y += o t h e r . y ;
z += o t h e r . y ;

http://www.st.ewi.tudelft.nl/~mbeller/publications/2015_beller_zaidman_karpov_the_last_line_effect_preprint.pdf

About Command Idempotency

Definition from Gregor (New ACID)
“In the world of distributed systems, idempotency translates to the fact that an operation can be invoked repeatedly without changing the result.”

http://www.eaipatterns.com/ramblings/68_acid.html
http://codebetter.com/gregyoung/2010/08/12/idempotency-vs-distibuted-transactions/

Idempotency Patterns
http://blog.jonathanoliver.com/idempotency-patterns/