Flinkspector

This project provides a framework to define unit tests for Apache Flink data flows. The framework executes data flows locally and verifies the output using predefined expectations.

Features include:

• Concise DSL to define test scenarios.
• Powerful matchers to express expectations.
• Test base for JUnit.
• Test stream windowing with timestamped input.

Check out the wiki to learn how Flinkspector can assist you in developing Flink jobs.

Examples

Minimal:

class Test extends DataSetTestBase {
    
    @org.junit.Test
    public myTest() {
		DataSet<Integer> dataSet = createTestDataSet(asList(1,2,3))
		    .map((MapFunction<Integer,Integer>) (value) -> {return value + 1});

		ExpectedRecords<Integer> expected = 
		    new ExpectedRecords<Integer>().expectAll(asList(2,3,4))

		assertDataSet(dataSet, expected);
    }

}

Streaming:

@org.junit.Test
public void testWindowing() {

	// Define the input DataStream:	
	DataStream<Tuple2<Integer, String>> testStream =
			createTimedTestStreamWith(Tuple2.of(1, "fritz"))
					.emit(Tuple2.of(1, "hans"))
					.emit(Tuple2.of(1, "heidi"), intoWindow(30, seconds)
					.emit(Tuple2.of(3, "peter"), intoWindow(1, minutes)
					.repeatAll(times(2))
					.close();

		
	// Lets you query the output tuples like a table:
	OutputMatcher<Tuple2<Integer, String>> matcher =
			//define keys for the values in your tuple:
			new MatchTuples<Tuple2<Integer, String>>("value", "name")
					.assertThat("value", is(3))
					.assertThat("name", either(is("fritz")).or(is("peter")))
					.onEachRecord();
	
	assertStream(someWindowAggregation(testStream), matcher);
}

You can find more extensive examples here:

• DataSet API test examples.
• DataStream API test examples.

Getting started

Get the Latest Release:

Note: The current build works with Flink version 1.8.0. There is no Flink 1.4.0 release for scala 2.10 so this has been dropped by flinkspector as well.

Include in your project's pom.xml:

<dependency>
   <groupId>io.flinkspector</groupId>
   <artifactId>flinkspector-dataset_2.11</artifactId>
   <version>0.9.4</version>
</dependency>

or for the Flink DataStream API:

<dependency>
    <groupId>io.flinkspector</groupId>
    <artifactId>flinkspector-datastream_2.11</artifactId>
    <version>0.9.4</version>
</dependency>

If you want to use assertions you should also include hamcrest:

<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-all</artifactId>
    <version>1.3</version>
    <type>jar</type>
    <scope>test</scope>
</dependency>

Manual Build:

1. Clone this repo: git clone https://github.com/ottogroup/flink-spector.
2. Build with maven: maven install.
3. Include in your project's pom.xml:

<dependency>
    <groupId>io.flinkspector</groupId>
    <artifactId>flinkspector-dataset</artifactId>
    <version>0.9.5-SNAPSHOT</version>
</dependency>

or for the Flink DataStream API:

<dependency>
    <groupId>io.flinkspector</groupId>
    <artifactId>flinkspector-datastream</artifactId>
    <version>0.9.5-SNAPSHOT</version>
</dependency>

Origins

The project was conceived at the Business Intelligence department of Otto Group.

Build Status

License

Licensed under the Apache License 2.0