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>

Usage

Warning
 Mock connector should be used in the test environment only!

For injecting Mock Connector use @TestConnector qualifier:

@Inject
@TestConnector
MockConnector mockConnector;

Emitting Data

Emitting String values a, b, c
mockConnector.incoming("my-incoming-channel", String.class) // (1)
        .emit("a", "b", "c");

  1. 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) // (1)
        .awaitData(TIMEOUT, Message::getPayload, "a", "b", "c"); // (2)

  1. Get outgoing channel of given name and payload type

  2. Request number of expected items and block the thread until items arrive then assert the payloads

Configuration

Key

Default value

Description

mock-data

Initial data emitted to the channel immediately after subscription

mock-data-type

java.lang.String

Type 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 // (1)
@AddBean(MockConnector.class) // (2)
@AddExtension(MessagingCdiExtension.class) // (3)
@AddConfig(key = "mp.messaging.incoming.test-channel-in.connector", value = MockConnector.CONNECTOR_NAME) // (4)
@AddConfig(key = "mp.messaging.incoming.test-channel-in.mock-data-type", value = "java.lang.Integer") // (5)
@AddConfig(key = "mp.messaging.incoming.test-channel-in.mock-data", value = "6,7,8") // (6)
@AddConfig(key = "mp.messaging.outgoing.test-channel-out.connector", value = MockConnector.CONNECTOR_NAME) // (7)
public class MessagingTest {

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

    @Inject
    @TestConnector
    private MockConnector mockConnector; // (8)

    @Incoming("test-channel-in")
    @Outgoing("test-channel-out")
    int multiply(int payload) {  // (9)
        return payload * 10;
    }

    @Test
    void testMultiplyChannel() {
        mockConnector.outgoing("test-channel-out", Integer.TYPE) // (10)
                .awaitPayloads(TIMEOUT, 60, 70, 80);
    }
}

  1. If you want to add all the beans manually

  2. Manually add MockConnector bean, so it is accessible by messaging for constructing the channels

  3. Messaging support in Helidon MP is provided by this CDI extension

  4. Instruct messaging to use mock-connector as an upstream for channel test-channel-in

  5. Generate mock data of java.lang.Integer, String is default

  6. Generate mock data

  7. Instruct messaging to use mock-connector as a downstream for channel test-channel-out

  8. Inject mock connector so we can access publishers and subscribers registered within the mock connector

  9. Messaging processing method connecting together channels test-channel-in and test-channel-out

  10. 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.