Contents

Overview

Mock connector is a simple application scoped bean that can be used for emitting to a channel or asserting received data in a test environment. All data received are kept in memory only.

Maven Coordinates

To enable Mock Connector add the following dependency to your project’s pom.xml (see Managing Dependencies).

<dependency>
    <groupId>io.helidon.messaging.mock</groupId>
    <artifactId>helidon-messaging-mock</artifactId>
</dependency>
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Usage

Mock connector should be used in the test environment only!

For injecting Mock Connector use @TestConnector qualifier:

@Inject
@TestConnector
MockConnector mockConnector;
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Emitting Data

Emitting String values a, b, c
mockConnector
     .incoming("my-incoming-channel", String.class) 
     .emit("a", "b", "c");
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  • Get incoming channel of given name and payload type

Asserting Data

Awaiting and asserting payloads with custom mapper
mockConnector
    .outgoing("my-outgoing-channel", String.class)           
    .awaitData(TIMEOUT, Message::getPayload, "a", "b", "c");
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  • Get outgoing channel of given name and payload type
  • Request number of expected items and block the thread until items arrive then assert the payloads

Configuration

KeyDefault valueDescription
mock-dataInitial data emitted to the channel immediately after subscription
mock-data-typejava.lang.StringType of the emitted initial data to be emitted

Helidon Test with Mock Connector

Mock connector works great with built-in Helidon test support for JUnit 5 or TestNG.

As Helidon test support makes a bean out of your test, you can inject MockConnector directly into it.

@HelidonTest
@DisableDiscovery 
@AddBean(MockConnector.class) 
@AddExtension(MessagingCdiExtension.class) 
@AddConfig(key = "mp.messaging.incoming.test-channel-in.connector", value = MockConnector.CONNECTOR_NAME)  
@AddConfig(key = "mp.messaging.incoming.test-channel-in.mock-data-type", value = "java.lang.Integer")      
@AddConfig(key = "mp.messaging.incoming.test-channel-in.mock-data", value = "6,7,8")                       
@AddConfig(key = "mp.messaging.outgoing.test-channel-out.connector", value = MockConnector.CONNECTOR_NAME) 
public class MessagingTest {

    private static final Duration TIMEOUT = Duration.ofSeconds(15);

    @Inject
    @TestConnector
    private MockConnector mockConnector; 

    @Incoming("test-channel-in")
    @Outgoing("test-channel-out")
    int multiply(int payload) {  
        return payload * 10;
    }

    @Test
    void testMultiplyChannel() {
        mockConnector.outgoing("test-channel-out", Integer.TYPE) 
                .awaitPayloads(TIMEOUT, 60, 70, 80);
    }
}
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  • If you want to add all the beans manually
  • Manually add MockConnector bean, so it is accessible by messaging for constructing the channels
  • Messaging support in Helidon MP is provided by this CDI extension
  • Instruct messaging to use mock-connector as an upstream for channel test-channel-in
  • Generate mock data of java.lang.Integer, String is default
  • Generate mock data
  • Instruct messaging to use mock-connector as a downstream for channel test-channel-out
  • Inject mock connector so we can access publishers and subscribers registered within the mock connector
  • Messaging processing method connecting together channels test-channel-in and test-channel-out
  • Actual JUnit 5 test method which is going to block the thread until 3 items are intercepted on test-channel-out channel’s downstream and assert those with expected values.