This document discusses testing event-driven architectures. It begins by defining common event-driven architecture patterns like event notifications and event sourcing. It then discusses brokering the complexity of event-driven architectures by describing how events are communicated between producers and consumers via channels. The document outlines what information should be included in events like payloads and headers. It also discusses the difference between orchestration and choreography in event-driven systems. It provides an example of how events can be used to mediate changes within a system using order validation. Finally, it demonstrates how to test event-driven architectures using specifications and discusses accelerating API quality through testing tools that support multiple protocols and definitions.

1. Testing Event Driven Architectures:
How to Broker the Complexity

2. Speakers
Frank Kilcommins
API Technical Evangelist
SmartBear Software
Temil Sanchez
Product Owner, ReadyAPI
SmartBear Software

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16M+
users
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3 650+
customers
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founded global offices
open source
initiatives
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Common Event Driven Architectures
| Event Notifications
| Event Carried State Transfer
| Hybrid (some limited state)
| Event Sourcing

5. Proprietary & Confidential
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Brokering the Complexity of Event-Driven Architecture
Request
Response
Request/Response
Consumer makes a request, maintains state
REST interface provides a stateless response
Broker
Producers Consumers
Channels
Event Driven Architecture (EDA)

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Defining an Event: What’s in a Message?
What should I expect in return?
| Payload – the message, or messages, as
defined by the schema
| Headers – for example: the UUID of the
specific publisher of a message
• Message headers may contain a
CorrelationID – which can be used in
message tracing.
Event/Message

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They’re Doing Choreography:
Independence is Tricky to Maintain
Two Options: Orchestration or Choreography
| Orchestration implies Centralized Control – a
conductor brings in sections of the orchestra,
modulates the dynamics – while each member plays
their own instrument, they depend on the
conductor to bring the music together
| Choreography promotes Design(-first) Thinking. The
patterns and interactions are inherent, but the
individual executors (dancers) listen to the music
and react independently to the patterns within.

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Specification-based Testing of Event-driven Architecture
• AsyncAPI 2.0 (now also 2.1) describes
the interaction model for asynchronous
services, including:
• Servers
• Channels
• Publishers/Subscribers
• Messages/Events
As part of our demo, we will demo spec-
based testing using AsyncAPI.

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Events can Mediate Change within a System
| Orders Service:
REST-> to POST/GET Orders
| Triggers an event which is picked up by
the three ‘validator’ services (Fraud,
Inventory, Order Details)
| Net result of three validations is written
back to Order Validation Topic
| To test real scenarios of use in the
system, you cannot ignore events -
because an order won’t exist without
validation
Source: Confluent Kafka Streams Example

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Event-driven Architecture: Maturity Model Revisited
Isolated Use Consolidating Governed Transformative
S t r a t e g i c
T a c t i c a l
Source: Mooter, David - Forrester, Event-Driven Architectural Patterns

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Recap
| Don’t make events the only pattern/mode
| Know when to use choreography vs. orchestration
| Use specifications to document, describe and aid testing your Events
| Think about the end-to-end testing flows
| No silver bullet but specs and testing tools foster quality

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Accelerating API Quality Through Testing
12
Import API Definitions and standards like
AsyncAPI, OpenAPI, GraphQL Schema, JSON
Schema, and more. Test live traffic across
multiple protocols like REST, SOAP, GraphQL,
Apache Kafka, MQTT, JMS, and more.
Create, manage, and execute functional,
security, and performance tests in one
centralized interface. Easily virtualize web
services to remove pipeline
dependencies.
Smart Assertion feature automatically
creates validation and assertion points. Or
utilize command-line support for automated
testing configuration with an exhaustive
range of integrations.
Supports Multiple Protocols and
Definitions
Multiple Capabilities in One
Platform
Flexible Testing and
Automation Options

13. Proprietary & Confidential
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Demo

14. Proprietary & Confidential
14
Accelerating API Quality Through Testing
14
Import API Definitions and standards like
AsyncAPI, OpenAPI, GraphQL Schema, JSON
Schema, and more. Test live traffic across
multiple protocols like REST, SOAP, GraphQL,
Apache Kafka, MQTT, JMS, and more.
Create, manage, and execute functional,
security, and performance tests in one
centralized interface. Easily virtualize web
services to remove pipeline
dependencies.
Smart Assertion feature automatically
creates validation and assertion points. Or
utilize command-line support for automated
testing configuration with an exhaustive
range of integrations.
Supports Multiple Protocols and
Definitions
Multiple Capabilities in One
Platform
Flexible Testing and
Automation Options

15. Thank You
Any Questions?
Learn more at
smartbear.com/ready-api