TestOutputTopic
TestOutputTopic is a Kafka Streams testing utility that represents an output topic and reads records produced by a topology under test.
Kafka Streams in Action, Second Edition
TestOutputTopic is a Kafka Streams test utility representing a topology output topic and providing methods for reading produced records.
- How it is used
- Validates records produced by Kafka Streams topologies without requiring a live Kafka broker.
- How deep it goes
- Explains construction, deserialization, output-reading methods, ordered assertions, final-per-key views, and time-driven output checks.
- Examples
- Demonstrates uppercase output, reduce results, latest values per key, punctuation, and suppressed windowed results.
- What you can do after
- Diagnose and validate topology behavior by reading produced records and comparing ordered, aggregated, timestamped, or windowed results.
Read how Kafka Streams in Action, Second Edition explains TestOutputTopic →
Kafka for Architects
TestOutputTopic is a Kafka Streams testing class that reads and verifies records emitted by a topology under test.
- How it is used
- Verifies records emitted by Kafka Streams topologies without requiring a running Kafka cluster.
- How deep it goes
- Explains topic configuration and serialized output verification, while deferring real broker communication to integration tests.
- Examples
- Uses input records, serialized Kafka-like messages, emitted output records, and stateful stream-processing tests.
- What you can do after
- Evaluate/understand topology behavior by supplying test records and verifying serialized output without a Kafka cluster.
Related concepts
- TopologyTestDriverproduced by · TopologyTestDriver is a Kafka Streams testing utility that runs a topology in memory without requiring a running Kafka cluster.
- processor topologyuses · A processor topology is a directed graph of source, processor, and sink nodes that defines how records flow through a stream-processing application.
- TestInputTopiccontrasts with · TestInputTopic is a Kafka Streams testing utility that represents an input topic and supplies records to a topology under test.
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