Testing service API and RSpec

Sometimes there is a need to write a small IPA service, often in the form of a prototype. And often this prototype then remains in the originally written form following the principle of "works - do not touch." Rewriting even a relatively small service involves the possibility of making an error or an occasional insignificant change in behavior, which is not immediately apparent. To help here comes testing ...

We make the payments by crypto-currency with our own hands

Hello, Habr!
From time to time I notice questions about how to accept Bitcoin payments on your site without using third-party services. This is quite simple, but we must take into account that there are pitfalls.
In this article I will try to describe in as much detail as possible, without emphasis on any programming language, how to make a payment acceptance Bitcoin (and also, if desired, Litecoin, Dash, Bitcoin Cash, Steep, ONION, etc.), starting with unfolding a full node and completing a check on receipt of payment.
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What are the cheap server options? Their mass, in ...