== Sample 6
This sample demonstrates a simple Kafka Streams topology tested with TopologyTestDriver.
The application contains a simple Kafka Streams topology that counts the keys seen so far in a stateful manner.
The corresponding `TopologyTestDriver` based JUnit test verifies the behavior of the business logic in the Kafka Streams topology.
Console output describe the topology as shown below:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.5.2)
2021-06-30 17:38:33.637 INFO 92063 --- [ main] com.example.ApplicationTests : Starting ApplicationTests using Java 11.0.10 on C02FL1KSMD6T with PID 92063 (started by igomez in /Users/igomez/Projects/spring-kafka/samples/sample-05)
2021-06-30 17:38:33.638 INFO 92063 --- [ main] com.example.ApplicationTests : The following profiles are active: test
2021-06-30 17:38:35.027 INFO 92063 --- [ main] com.example.ApplicationTests : Started ApplicationTests in 1.73 seconds (JVM running for 2.833)
2021-06-30 17:38:35.695 INFO 92063 --- [ main] com.example.ApplicationTests : Topologies:
Sub-topology: 0
Source: KSTREAM-SOURCE-0000000000 (topics: [input])
--> KSTREAM-AGGREGATE-0000000002
Processor: KSTREAM-AGGREGATE-0000000002 (stores: [KSTREAM-AGGREGATE-STATE-STORE-0000000001])
--> KTABLE-SUPPRESS-0000000003
<-- KSTREAM-SOURCE-0000000000
Processor: KTABLE-SUPPRESS-0000000003 (stores: [KTABLE-SUPPRESS-STATE-STORE-0000000004])
--> KTABLE-TOSTREAM-0000000005
<-- KSTREAM-AGGREGATE-0000000002
Processor: KTABLE-TOSTREAM-0000000005 (stores: [])
--> KSTREAM-SINK-0000000006
<-- KTABLE-SUPPRESS-0000000003
Sink: KSTREAM-SINK-0000000006 (topic: output)
<-- KTABLE-TOSTREAM-0000000005
