## Testcontainers

*Available since 2.22.0*

Testing camel components is sometime complex because the 3th party system a component interacts with does not provide testing facilities and/or is only available as a native application. To reduce this complexity, *Camel Testcontainers* extends standard camel test support providing a way to create and interact with containerized applications.

In order to define leverage testcontainers, add the following dependency to your pom:

[source,xml]
----
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-testcontainers</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
    <scope>test</scope>
</dependency>
----

[TIP]
====
To learn more about testcontainers, please have a look at the official documentation https://www.testcontainers.org
====

To leverage testcontaners in your tests, you can use `ContainerAwareTestSupport` which is an extension of `CamelTestSupport` which:

- create/destroy containers according to camel context lifecycle
- inject a custom `PropertiesFunction` to access container specific options from properties


To create a container you need to override:
[source, java]
----
protected GenericContainer<?> createContainer()
----

If you need to create more that one container, you can override the following method:
[source, java]
----
protected List<GenericContainer<?>> createContainers()
----

The methods above are invoked before the camel context starts and blocks until the containers are reported to be alive. Containers are destroyed once the camel context stops.

[source,java]
.Example
----
@Override
protected GenericContainer<?> createContainer() {
    return new GenericContainer<>("consul:1.0.7")
        .withNetworkAliases("myconsul") // <1>
        .withExposedPorts(8500)
        .waitingFor(Wait.forLogMessageContaining("Synced node info", 1)) // <2>
        .withCommand(
            "agent",
            "-dev",
            "-server",
            "-bootstrap",
            "-client",
            "0.0.0.0",
            "-log-level",
            "trace"
        );
}
----
<1> container name/alias
<2> container startup condition

[IMPORTANT]
====
It is important to give a name/alias to the container so you can then use properties functions to retrieve information such as container's host and port mapping.
====
[TIP]
====
You may need to wait for some condition to be satisfied before starting your test, to do so you need to configure the test suite to wait for such event using `GenericContainer.waitingFor`. Testcontainers provide a number of ready to use waiting strategy, for more info see the official testcontainers documentation.
====

Camel Testcontainer provides a PropertiesFunction implementation that can be used to:

- retrieve the container host with the following syntax `container:host:${container-name}`
- retrieve the port mapping with the following syntax `container:port:${exposed-port}@${container-name}`

[source,java]
.Example
----
public class MyTest extends ContainerAwareTestSupport {
    @Test
    public void testPropertyPlaceholders() throws Exception {
        GenericContainer<?> container = getContainer("myconsul");

        String host = context.resolvePropertyPlaceholders("{{container:host:myconsul}}");
        assertThat(host).isEqualTo(container.getContainerIpAddress());

        String port = context.resolvePropertyPlaceholders("{{container:port:8500@myconsul}}");
        assertThat(port).isEqualTo("" + container.getMappedPort(8500));
    }

    @Override
    protected GenericContainer<?> createContainer() {
        return new GenericContainer<>("consul:1.0.7")
            .withNetworkAliases("myconsul")
            .withExposedPorts(8500)
            .waitingFor(Wait.forLogMessageContaining("Synced node info", 1))
            .withCommand(
                "agent",
                "-dev",
                "-server",
                "-bootstrap",
                "-client",
                "0.0.0.0",
                "-log-level",
                "trace"
            );
    }
}
----
