What Are SAP APIs
Most typical SAP APIs are IDOC messages.
Majority of SAP S/4HANA systems communicate with other systems (non-SAP, legacy applications and external B2B partner systems via EDI) using IDOC messages. In many cases SAP S/4HANA systems would also use some kind of middleware technology like SAP Process Orchestration (SAP PO), SAP Integration Suite (SAP IS), Dell Boomi, Webmethods, Mulesoft, etc.).
What is important and unique for SAP ecosystem, is that majority of SAP application interfaces are asynchronous, what enables system flexibility and improves overall communication efficiency.
What Are the Challenges For Testing SAP APIs?
SAP API testing is different from API testing.
Due to the asynchronous nature of most SAP Application Interfaces, SAP API testing is even different from general API testing of synchronous interfaces where you can send a message and only need to validate the response. With SAP API testing of asynchronous interfaces there will be no response message.
API Testing – synchronous
SAP API Testing – asynchronous
Why is SAP API testing in SAP projects so easy and quick?
Messages exchanged with SAP systems can be easily repeated.
Most of the messages exchanged for the business interface communication in the SAP ecosystem are asynchronous and stored in the database, the only thing we need in order to retest the SAP applications is to re-run them intelligently in a non-invasive way. Creating a test document for SAP API testing only requires selecting the documents numbers (for e.g., IDOCs) which we want to reprocess.